Research & Findings

Researchers at the University of Edinburgh investigated how the SETD5 protein, the ANKRD11 protein (which is mutated in KBG syndrome), and a connecting protein called TBLR1 work together inside cells. They wanted to understand what happens to brain development when that partnership breaks down.

• TBLR1 acts as a physical scaffold that holds SETD5 and ANKRD11 together as part of a larger gene-regulating complex called NCoR. The resulting assembly resembles a well-characterized yeast complex called SET3C, which controls which genes get turned up or down during development.
• Pathogenic mutations in any one of the three proteins (SETD5, ANKRD11, or TBLR1) disrupt the assembly of this complex. In other words, SETD5 Syndrome, KBG syndrome, and TBLR1-related disorder may share a common molecular root, even though they are caused by mutations in different genes.
• When the complex fails, genes that are already highly active tend to become further overexpressed. This points to a breakdown in the normal "volume control" on gene activity during brain development.
• In mice, an engineered mutation that specifically prevented SETD5 from joining this complex (while leaving SETD5's other functions intact) caused severe developmental impairments. This isolates SETD5's role within the complex as critical to normal development.

This paper gives a biological explanation for why SETD5 disruptions affect brain development. It also shows that SETD5 Syndrome, KBG syndrome, and TBLR1-related conditions share the same underlying mechanism. That means research progress in any one of those three conditions could benefit the others.

Researchers at Yale University and the Icahn School of Medicine used CRISPR gene editing, a precise tool for turning genes off in a lab setting, to disable 23 genes, including SETD5, in lab-grown brain cells made from human stem cells. Each of these genes causes a different rare condition that affects brain development. The goal was to find out whether all these different genes affect the same underlying processes inside brain cells.

• SETD5 was one of 23 NDD loss-of-function genes specifically targeted and studied; the paper focuses on all 23 genes collectively, not SETD5 alone.
• The study found the greatest degree of overlap across all 23 genes in mature glutamatergic neurons, the primary excitatory signaling cells in the brain.
• Shared pathways across the gene set included synaptic function, epigenetic regulation, and mitochondrial function (the last of which was unexpected and consistent with separate SETD5 research showing mitochondrial involvement).
• Drugs that reversed the shared molecular signatures in the cell models also improved behavioral phenotypes in zebrafish carrying NDD gene mutations, suggesting the convergent pathways may be therapeutically relevant.
• This is the first study to examine SETD5 alongside other NDD genes in human iPSC-derived neurons using a standardized CRISPR approach, providing directly comparable data across conditions.

This study wasn't specifically about SETD5 Syndrome. SETD5 is one of 23 genes that were studied together. What makes it meaningful is that it puts SETD5 Syndrome on the same map as other well-researched conditions and shows that SETD5 Syndrome shares some of the same cellular processes with them. The part about existing drug classes showing an effect in lab cells is very early-stage research. It is not a treatment, and it is not a clinical recommendation.

Researchers at UTHealth Houston surveyed 51 members of the SETD5-related disorder Facebook support group between August and November 2024. The goal was to document a wider range of medical features reported by families and to describe how the online community supports affected families.

• Respondents represented individuals from 12 countries; 80% of affected individuals were under 18, with a mean age of diagnosis of 9.2 years.
• Most common features reported in this study: developmental delay (96%), hypotonia (78%), intellectual disability (75%), gait abnormality (59%), vision problems (51%), constipation (47%), and anxiety (47%).
• Pain-related features were reported for the first time in the published literature using family data: high pain tolerance (43%), persistent leg pain (31%), and joint pain (27%).
• Families reported that the Facebook support group was a primary source of information about therapies, school accommodations, and advocacy.

This is the first published study to document pain-related patterns in SETD5 Syndrome using family-reported information. High pain tolerance, persistent leg pain, and joint pain came up across multiple respondents. These features had not been described before in the SETD5 Syndrome medical literature. The researchers treated them as part of a broader picture of the condition.

Researchers re-evaluated a group of patients who had been diagnosed with Noonan syndrome but whose standard genetic testing had come back negative for the genes typically involved. Using expanded sequencing, they found the true genetic cause in several patients, including some with SETD5 variants.

• Six patients with features clinically consistent with Noonan syndrome were found to carry pathogenic SETD5 variants, not RASopathy mutations.
• SETD5 Syndrome can present with facial features, developmental delay, and other characteristics that overlap with Noonan syndrome, leading to initial misdiagnosis.
• This finding emphasizes that a Noonan-like appearance does not confirm a RASopathy and that comprehensive genetic sequencing is important.
• A correct genetic diagnosis can support access to condition-specific resources, registries, and research relevant to SETD5 Syndrome.

If your child received an initial diagnosis of Noonan syndrome that was later changed to SETD5 Syndrome, this paper documents that this is a recognized pattern in the medical literature. Families with a confirmed SETD5 Syndrome diagnosis will likely find SETD5-specific resources and registries more directly useful than programs designed for conditions that affect a different cellular pathway called the RAS pathway, or RASopathies.

A research team used whole exome sequencing, a type of genetic test that reads all the protein-coding genes, to identify new candidate genes in patients with a birth defect where the diaphragm doesn't close all the way, called a congenital diaphragmatic hernia. SETD5 was among the genes identified.

• SETD5 variants were identified in CDH patients through exome sequencing, implicating it as a candidate gene for this structural birth defect.
• This is an early-stage genetic association; a causal role for SETD5 in CDH has not been established.
• The finding extends the range of structural anomalies that may be associated with SETD5 variants, beyond previously documented features.

This is a preliminary study that shows a possible association, not a confirmed causal link. No formal changes to monitoring or screening for children with SETD5 Syndrome have been established based on this finding.

Most published SETD5 cases involve de novo mutations, meaning changes that appear for the first time in a child rather than being inherited. Two papers add to the smaller body of literature on structural changes in a chromosome, called copy number variants (CNVs), specifically gains (duplications) at chromosome region 3p25 and on inherited losses in the SETD5 region.

• Rangel-Méndez et al. 2026: A 21-year-old with mild intellectual disability and late diagnosis was found to carry a 3p26.3–3p25.2 microduplication encompassing SETD5. The authors reviewed the literature on 3p25 duplications and found the evidence base is thin — only a small number of cases have been described.
• The phenotype associated with SETD5 duplication appears milder than haploinsufficiency in reported cases, though the literature is too limited to draw firm conclusions.
• Dai et al. 2020: Two sisters with intellectual disability, short stature, and microcephaly were found to carry a 3p26.3–3p25.3 deletion inherited from a mother with a balanced translocation between chromosomes 3 and 14.
• The mother — who carried the translocation in balanced form — had a history of recurrent miscarriage, illustrating that a balanced translocation involving the SETD5 region can be passed through generations with different outcomes depending on how it segregates.
• Both papers extend the documented range of 3p25 CNV types beyond de novo deletions.

The published literature on SETD5 duplications and inherited 3p25 chromosome changes is limited. Families with these specific variant types may have less published data available to inform their clinical picture than families with de novo point mutations or small deletions. A clinical geneticist familiar with SETD5 Syndrome is the right person to help interpret these variants.

Researchers expanded a clinical diagnostic test called EpiSign, which identifies characteristic patterns in the way DNA is tagged (called methylation patterns, or episignatures) associated with genetic syndromes. SETD5 was among the conditions newly added to this library.

• A blood-based DNA methylation episignature specific to SETD5 Syndrome was identified and validated, adding SETD5 to the growing list of conditions detectable through the EpiSign clinical test.
• Episignatures can serve as a functional test to help classify variants of uncertain significance (VUS), meaning a DNA change that cannot be confirmed as disease-causing based on sequence analysis alone.
• Because SETD5 regulates chromatin structure, its loss-of-function leaves a detectable chemical imprint on the genome that persists in blood cells and can be measured in a clinical laboratory.

EpiSign is a clinical test done on a blood sample that looks at DNA methylation patterns to help confirm or clarify a genetic diagnosis. If your child received a variant of uncertain significance (VUS) in SETD5, meaning a DNA change whose effects aren't yet confirmed, an episignature test may be one tool clinicians can use to assess whether that variant actually affects gene function. This is a diagnostic tool, not a treatment, and it doesn't change or predict clinical outcomes.

Researchers used the National Brain Gene Registry to find and analyze 13 individuals with SETD5 Syndrome ranging in age from 2 to 37 years. The study recorded their genetic variants and clinical features, including features that had not been described in the published SETD5 literature before.

• Brain structural differences were identified in some participants, a feature not well-documented in prior SETD5 studies.
• Musculoskeletal problems were documented at higher rates than previously reported.
• 11 unique pathogenic or likely pathogenic variants were identified: 6 nonsense, 4 frameshift, 1 splice site.
• Symptom presentation varied substantially across participants, including those with similar mutations.
• Cerebral palsy was documented in at least one participant — a feature not previously described in the published SETD5 Syndrome literature.

This study documents brain structural differences and musculoskeletal findings in SETD5 Syndrome at higher rates than earlier published reports had shown.

Researchers compared behavioral impairments across several different genetic mouse models of autism, including mice with only one working copy of the Setd5 gene, to identify shared features that might point to common underlying mechanisms.

• Setd5 haploinsufficient mice showed impairments in visual perception and place avoidance behavior, difficulties that were shared across multiple different autism gene models.
• These shared behavioral impairments were driven by hypoexcitability (reduced neural activity) in the periaqueductal grey, a brainstem region involved in sensory processing and defensive behaviors.
• The finding that different autism-associated genes, including SETD5, converge on the same brain circuit suggests potential shared therapeutic targets across multiple genetic forms of autism.
• Published in PLoS Biology, a high-impact open-access journal, making the findings freely available to the research community.

This study suggests that SETD5 Syndrome shares specific neurological features with other genetic forms of autism at the brain circuit level. Research on shared brain circuit dysfunction across autism genetic models may eventually point toward possible therapy directions, but this is still early-stage research done in animals.

A multicenter European team reported on 28 SETD5 Syndrome patients who had not been described in any previous publication. The study focused specifically on neurological and psychiatric features.

• 75% of patients had intellectual disability or global developmental delay; 21% had borderline intellectual functioning; 3.6% had normal IQ.
• Autism spectrum disorder was confirmed in 24% of patients.
• Abnormal gait, including tip-toe walking, was documented in 36% of patients.
• Hyperkinetic or repetitive movements were documented in 21% of patients.
• Epilepsy was present in 14% of patients, across multiple seizure types.
• Neurological and psychiatric features co-occurred in multiple patients.

As of this page's last review, this study offers some of the most detailed frequency estimates for specific symptoms in SETD5 Syndrome. Because the group was 28 patients, all of the percentages should be read with caution. The finding that 3.6% of patients have normal IQ confirms that outcomes span a wide range.

Clinicians published a case report of a child with SETD5 overlap syndrome who was treated with recombinant human growth hormone (rhGH), a medication, for documented short stature.

• The child showed significant growth improvement following initiation of growth hormone therapy.
• This is the first published report of growth hormone treatment in any patient with SETD5 Syndrome or SETD5 overlap syndrome.
• Short stature is a recognized feature of SETD5 Syndrome; prior to this report, no treatment data had been published.

This is a single case report and the first published report of growth hormone treatment in a patient with SETD5 Syndrome. One patient is not enough to establish treatment guidelines. If your child has significant short stature, talk with your care team about what monitoring and options make sense for your child specifically.

Clinicians described a 6-year-old child with a confirmed pathogenic SETD5 variant who developed an epilepsy presentation that had not previously been documented in association with SETD5 Syndrome.

• The seizure pattern in this child had not been previously documented in the SETD5 literature.
• This case extends the known range of epilepsy presentations associated with SETD5 Syndrome.
• Approximately 14% of patients had epilepsy in the largest published SETD5 Syndrome cohort (De Falco et al. 2024, 28 patients).

Seizure presentations in SETD5 Syndrome vary from patient to patient. This case adds another type to the documented range. Your child's neurologist is the right person to discuss what this means for your child's specific situation.

Researchers investigated why mutations in SETD5, ANKRD11 (which causes KBG syndrome), and TBLR1 produce overlapping clinical features in patients. They found that all three proteins participate in the same molecular complex inside brain cells.

• The proteins produced by SETD5, ANKRD11, and TBLR1 form a single molecular complex in brain cells, called the SET3-like complex.
• TBLR1 functions as a molecular bridge linking ANKRD11 and SETD5 to a larger regulatory complex called NCoR.
• This provides a molecular explanation for why mutations in these three genes produce similar clinical features.
• The NCoR complex has been studied as a therapeutic target in other disease contexts.

This finding identifies a specific shared biological process connecting SETD5 Syndrome, KBG syndrome, and related conditions. Research or drug development aimed at this mechanism in one condition may have implications for the others.

The authors describe a patient with a confirmed pathogenic SETD5 variant who was later diagnosed with moyamoya syndrome, a progressive narrowing of major blood vessels in the brain that increases the risk of stroke.

• This is only the second published case linking a SETD5 variant to moyamoya syndrome, following the Pinard et al. 2019/2020 report.
• The patient did not have intellectual disability, demonstrating that moyamoya in SETD5 Syndrome is not limited to individuals with cognitive impairment.
• The patient's presentation underscores that moyamoya, while rare, can occur in SETD5 Syndrome and may not be identified without neurological investigation.
• The authors discuss the possible mechanism by which SETD5 haploinsufficiency could contribute to abnormal blood vessel development in the brain.

Moyamoya is a rare but documented complication in SETD5 Syndrome. Symptoms described in published reports include recurring headaches, weakness on one side of the body, and changes in speech. If your child has any of these symptoms, bring them to your care team's attention.

Clinicians described a child with a confirmed SETD5 mutation whose features overlapped with three other conditions: MRD23, KBG syndrome, and Cornelia de Lange syndrome. The report documents brain MRI differences not previously described in SETD5 Syndrome and describes the first published use of growth hormone therapy in a patient with a SETD5 mutation.

• Brain MRI showed hypomyelination of the cerebral hemispheres, altered morphology of the basal ganglia, and cerebellar atrophy — structural findings not well-documented in prior SETD5 literature.
• The patient's features overlapped with three conditions: SETD5-related neurodevelopmental disorder (MRD23), KBG syndrome, and Cornelia de Lange syndrome, extending the documented clinical overlap between these conditions.
• The patient received recombinant growth hormone therapy off-label for severe short stature. Growth velocity increased from 3.9 cm/year before treatment to 7.2 cm in year one and 5.8 cm in year two. Predicted final height improved by approximately 6 cm. No side effects were reported.
• The authors described this as the first published case of growth hormone therapy in a patient with a SETD5 mutation and noted that larger case series are needed to evaluate its effectiveness.

This case may be most relevant for families whose child has brain MRI differences, significant short stature, or features that overlap with KBG or Cornelia de Lange syndrome alongside a SETD5 diagnosis. The growth hormone observation is preliminary. It comes from one patient and is not a treatment recommendation.

Clinicians described a fetus identified prenatally with a SETD5 mutation. They documented which features were visible before birth through ultrasound and genetic testing, and reviewed the existing published literature on prenatal presentations of SETD5 Syndrome.

• This is one of a small number of published case reports documenting the prenatal phenotype of SETD5 Syndrome; an earlier case involving first-trimester cystic hygroma was described by Pan et al. in 2020.
• The case documents that some SETD5-associated features may be identifiable on prenatal ultrasound, contributing to earlier diagnosis pathways.
• The authors reviewed existing SETD5 literature in the context of prenatal genetic counseling.

This case may be most relevant for families who received a SETD5 Syndrome diagnosis before birth or who are thinking about future pregnancies with a known SETD5 variant in the family. It adds to the small but growing body of knowledge about what SETD5 Syndrome can look like before birth.

A large clinical study used whole exome sequencing, a type of genetic test that reads all the protein-coding genes, to examine patients with kidney and urinary tract differences present at birth who also had additional clinical features. The goal was to identify genetic causes and expand what was known about the range of features linked to relevant genes.

• SETD5 was identified as a gene associated with increased risk of congenital kidney and urinary tract anomalies in this dataset.
• This links SETD5 to the urinary tract, an organ system not prominently documented in prior SETD5 literature.
• This is an association finding from a broader genetic sequencing study, not a targeted SETD5 investigation.

This is early-stage data. No formal guidelines for kidney screening in SETD5 Syndrome have been established based on this finding.

Researchers performed whole-genome sequencing on a group of patients who had been referred for clinical evaluation of Cornelia de Lange Syndrome (CdLS), a rare genetic disorder that shares features with several other conditions. The goal was to identify the true genetic cause in patients where standard targeted testing had not found an answer.

• Pathogenic SETD5 variants were identified in a subset of patients in this CdLS cohort, contributing to the documented phenotypic overlap between SETD5 Syndrome and CdLS.
• The finding extends the list of conditions that may be initially suspected before a SETD5 Syndrome diagnosis is reached, alongside previously documented overlaps with Noonan syndrome, KBG syndrome, and others.
• Whole-genome sequencing identified genetic causes in patients where targeted panel testing had not provided a diagnosis.

A path through a suspected Cornelia de Lange Syndrome evaluation before arriving at a SETD5 Syndrome diagnosis is now documented in the medical literature. This is consistent with the known feature overlap between SETD5 Syndrome and several other genetic conditions.

Researchers analyzed epilepsy features and EEG (electroencephalogram, a test that measures brain electrical activity) findings in patients with 3p deletion syndrome, a chromosomal condition in which the deleted region can include the SETD5 gene depending on the size and location of the deletion.

• The study documented epilepsy types, seizure frequencies, and characteristic EEG patterns observed in patients with 3p chromosomal deletions.
• Patients whose deletions encompassed the SETD5 region were included in the analysis, contributing clinical data on seizure profiles in this subset.
• The paper adds to the neurological characterization of the 3p25 chromosomal region and the conditions associated with it.

This study is most directly relevant to families whose child has a larger chromosomal deletion in the 3p region rather than a single-gene SETD5 point mutation. Chromosomal 3p deletions vary widely in size and often include genes in addition to SETD5, which affects the clinical picture. A clinical neurologist or geneticist familiar with your child's specific deletion is the right person to interpret these findings for your situation.

A descriptive report of the Brain Gene Registry (BGR), a research platform built by 13 Intellectual and Developmental Disabilities Research Centers across the United States. The BGR pairs clinical data from standardized assessments with genetic data from participants who have variants in brain-relevant genes.

• The BGR had 479 participants representing over 200 different genes at the time of this data snapshot. SETD5 is one of only five genes with 12 or more participants enrolled — alongside CACNA1A, DNMT3A, SLC6A1, and MYT1L — making SETD5 among the most represented conditions in this national resource.
• More than 30% of variants in the BGR are de novo, and 43% are classified as variants of uncertain significance (VUS). The registry is particularly valuable for building evidence on VUS pathogenicity in conditions like SETD5 Syndrome.
• The most common diagnoses in the BGR cohort are developmental delay (earliest and most frequent), followed by speech and language disorders, autism spectrum disorder, and ADHD — consistent with the published SETD5 Syndrome literature.
• BGR data has been used to support ClinGen gene-disease validity curation for 36 genes, accelerating the formal classification of rare disease genes for clinical use.
• The registry links to GenomeConnect (ClinVar), enabling variant data to contribute to the broader clinical genetics database accessible to clinicians worldwide.

The Brain Gene Registry is a research resource that families can consider joining. Enrollment contributes clinical and genetic information that researchers use to build a more complete picture of conditions like SETD5 Syndrome. The Callahan et al. 2025 study that documented new brain and musculoskeletal findings in 13 SETD5 patients used data from this registry.

Researchers performed whole exome sequencing, a type of genetic test that reads all the protein-coding genes, and chromosomal microarray analysis on 22 pediatric cancer patients, half of whom also had birth differences. The goal was to find inherited genetic variants that might explain the combination of childhood cancer and structural differences.

• Among 22 patients, confirmed pathogenic variants in established cancer predisposition genes were found in 14%. When candidate and recessive genes were included, the yield rose to 45%.
• Most deleterious variants were in genes not conventionally associated with the patient's specific tumor type, suggesting that standard cancer predisposition gene lists may be incomplete for pediatric patients with additional clinical signs.
• SETD5 was identified in a neuroblastoma case and described as a potentially novel genotype-phenotype association — the second published report connecting SETD5 to neuroblastoma, after Pires et al. 2020.
• The study found evidence of oligogenic inheritance in some patients, where multiple gene variants acting together appeared to increase cancer risk rather than a single pathogenic variant alone.

This is an early-stage candidate association. Two published reports now connect SETD5 to neuroblastoma, but two case reports are not enough evidence to establish that SETD5 Syndrome increases cancer risk. This finding does not change current clinical management. Questions about cancer risk should be discussed with a clinical geneticist or oncologist familiar with your child's specific situation.

Researchers used CRISPR gene editing, a precise tool for turning genes off in a lab setting, to completely disable the setd5 gene in zebrafish and then observed the resulting behavioral effects, focusing on social behavior relevant to autism.

• Complete CRISPR-induced inactivation of setd5 in zebrafish led to measurable social impairments, consistent with autism-like behavioral changes.
• This study extends the zebrafish model of SETD5 first established by Sessa et al. 2019, using a more precise gene-editing approach (CRISPR/Cas9 rather than morpholino knockdown).
• The zebrafish model continues to be validated as a platform for studying SETD5-related social behavior and for screening potential therapeutic compounds.

Zebrafish are used in early drug discovery research because they develop quickly and share key genetic pathways with humans. This study adds to the research tools that scientists may use to screen potential therapeutic compounds. This is a step in early-stage lab research, not a treatment.

Italian clinicians described a child with a confirmed pathogenic SETD5 variant whose facial features and overall clinical presentation closely resembled KBG syndrome. The report expands on the known overlap between the two conditions.

• The child carried a pathogenic SETD5 variant but presented with features that strongly suggested KBG syndrome at first clinical evaluation.
• The case adds to a growing set of reports documenting that SETD5 Syndrome and KBG syndrome can be clinically indistinguishable in some children.
• The authors describe additional novel features in the child that further refine the published SETD5 phenotype.

If your child was initially evaluated for KBG syndrome before receiving a SETD5 Syndrome diagnosis, this paper adds to the published medical literature documenting this overlap. The shared appearance between the two conditions is now well documented across multiple published cases.

Six patients with clinical features of Cornelia de Lange syndrome underwent whole exome sequencing, a type of genetic test that reads all the protein-coding genes, and were found to carry variants in genes outside the cohesin complex that is typically responsible for CdLS. SETD5 was among the genes identified. The authors also compiled all previously published patients with Cornelia de Lange syndrome-like features from similar non-cohesin variants.

• All six new patients had non-cohesin gene variants — including SETD5 among the genes identified — accounting for their CdLS-like presentations.
• Combined with prior literature, the study documents 46 patients across 20 non-cohesin genes whose presentations include CdLS-like features. SETD5 is one of those 20 genes.
• Four of the six newly described variants were previously unreported, expanding the known range of variants in these genes.
• The SETD5 cohort's average clinical score on the published CdLS scoring system was not statistically different from the score of patients with confirmed NIPBL mutations (classic CdLS), meaning standard clinical criteria cannot reliably distinguish between the two diagnoses.
• The authors conclude that whole-exome sequencing is required to confirm a diagnosis when CdLS-like features are present.

This study adds to the established evidence that SETD5 Syndrome and Cornelia de Lange syndrome can look clinically very similar. A path through a CdLS assessment before receiving a SETD5 diagnosis is a well-documented pattern in the medical literature.

The first whole-genome sequencing study of 53 parent-child trios in which the child had obsessive-compulsive disorder (OCD). The goal was to identify new DNA changes that arose for the first time in the child (de novo variants) and understand which biological processes they affect.

• De novo mutations in OCD patients were significantly enriched in genes involved in chromatin modification during brain development — the same biological class as SETD5.
• SETD5 was among four genes showing the strongest aggregated evidence of association with OCD in this cohort. All four converge on epigenetic regulation of transcription as a shared mechanism.
• Mutations were concentrated in genomic regions known to be especially active in brain development, including promoter-anchored chromatin loops.
• This study extends the potential clinical range associated with SETD5 variants into psychiatric presentations — an area not prominent in prior SETD5 literature, which has focused primarily on intellectual disability and autism spectrum disorder.

This is a small early-stage study. SETD5 shows up as a statistical signal in the context of OCD, not as a confirmed cause. If your child has both a SETD5 diagnosis and OCD features, this may be worth discussing with a specialist who knows your child's full clinical picture. Any clinical questions should go to a specialist familiar with your child's specific presentation.

Researchers enrolled 214 patients with short stature and differences across multiple organ systems and performed whole exome sequencing, a type of genetic test that reads all the protein-coding genes, to look for variants in genes involved in epigenetic modification, which controls how genes are turned on and off. SETD5 was one of 19 genes identified across the group.

• WES identified pathogenic or likely pathogenic variants in 33 of 214 patients (15.4%), across 19 epigenetic genes including SETD5.
• Webbed neck was reported in association with a SETD5 variant for the first time in published literature.
• Across all 33 patients (representing 19 epigenetic genes, including but not limited to SETD5), common overlapping features included developmental delay or intellectual disability (93.9%), small hands (42.4%), clinodactyly of the 5th finger (42.4%), long eyelashes (39.4%), and hearing impairment (27.3%). These percentages reflect the full multi-gene group, not SETD5 patients specifically.
• 19 of the 33 variants identified had never been previously reported.
• The study documents that SETD5 shares clinical overlap with other epigenetic modification disorders including KMT2A, KMT2D, ANKRD11 (KBG syndrome), and Cornelia de Lange syndrome genes.

This study adds webbed neck to the documented features associated with SETD5 variants, something not previously published. It also reinforces that SETD5 Syndrome belongs to a broader group of epigenetic disorders with overlapping features. This may help explain why some children receive an initial diagnosis of a related condition before SETD5 Syndrome is confirmed.

Researchers created human neural cells, brain cells, in the laboratory with SETD5 haploinsufficiency, meaning only one working copy of the SETD5 gene was active. They measured what happened to the cells' mitochondria, the structures inside cells that produce energy.

• Brain cells with SETD5 haploinsufficiency showed fragmented mitochondria compared to cells with normal SETD5 function.
• Fragmented mitochondria produced less ATP (the molecule cells use to power activity) compared to normal cells.
• Reduced cellular energy production in neurons may contribute to cognitive and behavioral symptoms associated with SETD5 Syndrome.
• Mitochondrial function is identified as a specific cellular mechanism that could potentially be targeted therapeutically.

This is lab research done in cell cultures, not in people with SETD5 Syndrome. It describes a specific biological problem that researchers can now study as a potential target. No treatments based on this finding have entered clinical trials.

Mouse models carrying either SETD5 mutations or KBG syndrome mutations (in the ANKRD11 gene) were studied side by side to identify the neurological mechanisms they share.

• Mice with SETD5 mutations showed learning impairments and behavioral differences consistent with autism-like features.
• Both SETD5 and KBG mutant mice showed disruption to the same neurological pathway.
• These findings support the clinical observation of overlapping features between SETD5 and KBG syndrome.

Mouse model findings don't directly translate to humans, but they provide biological evidence supporting the shared mechanism identified in other recent studies. Research progress on SETD5 Syndrome and KBG syndrome may benefit from each other.

Researchers examined the retina, the light-sensitive tissue at the back of the eye, in models where normal SETD5 function was absent. They looked at whether SETD5 plays a role in how retinal cells survive and multiply during eye development.

• SETD5 was found to be required for normal survival and proliferation of retinal cells during development.
• In the absence of functional SETD5, retinal cell death increased and cell proliferation was reduced.
• This is the first published study documenting a role for SETD5 in eye development.

Published research has identified a role for SETD5 in eye development. No formal clinical screening guidelines for eye problems in SETD5 Syndrome have been established based on this finding.

Additional cases of reduced bone mineral density and vertebral fractures in SETD5 Syndrome patients were presented at the European Society for Pediatric Endocrinology annual conference.

• These cases extend and confirm the bone fragility association first published in 2021.
• Vertebral compression fractures were documented in patients, including cases with no clear injury event.
• Presentation at a pediatric endocrinology conference increases awareness among specialists who treat children with growth and bone conditions.

Bone fragility in SETD5 Syndrome is now supported by multiple published data points from 2021 and 2023. If bone density or fractures are a concern for your child, this is worth raising with your care team.

Clinicians at Children's Hospital Los Angeles described a patient with a new pathogenic SETD5 variant who had two clinical features that had not previously been documented in connection with SETD5 Syndrome: pigmentary retinopathy (a condition affecting the retina at the back of the eye) and central hypothyroidism (low thyroid hormone caused by a problem in the brain rather than the thyroid itself).

• The patient had pigmentary retinopathy (a vision-affecting eye condition) and central hypothyroidism, neither of which had been previously reported in published SETD5 Syndrome cases.
• Other features documented included autism, stuttering, brachycephaly, low-set ears, synophrys, ptosis, depressed nasal bridge, thin upper lip, micrognathia, postaxial polydactyly, leg-length discrepancy, feeding difficulties, congenital heart defects, and behavioral challenges.
• The authors note that they cannot definitively confirm whether the retinopathy and hypothyroidism are caused by SETD5, but the case expands the documented genotypic and phenotypic spectrum of the condition.

This case adds pigmentary retinopathy and central hypothyroidism to the list of features that have been observed in SETD5 Syndrome. Neither had been described before in the published literature. If your child has thyroid or vision concerns, these findings are relevant context to share with your care team.

Clinicians from The Hospital for Sick Children in Toronto described a 15-year-old girl with mild intellectual disability and a confirmed pathogenic SETD5 variant who developed drug-resistant focal epilepsy at age 9.

• The patient developed focal seizures at age 9 that did not respond to multiple antiseizure medications.
• Inter-ictal EEG (between seizures) showed sleep-activated right occipito-temporal spike/sharp waves; ictal EEG (during seizures) showed right occipital localization.
• Over approximately four years from seizure onset, EEG abnormalities became more right hemispheric and then generalized, possibly representing secondary bilateral synchrony.
• The authors note that the current understanding of SETD5's role in epilepsy is limited, with most published SETD5 data coming from neurodevelopmental rather than epilepsy studies.

This case documents that drug-resistant focal epilepsy can occur in SETD5 Syndrome. In this patient, EEG activity (which maps the electrical activity in the brain) was localized to the posterior right hemisphere. Every child's seizure picture is different, and your child's neurologist is the right person to guide epilepsy management.

This review article brings together everything published on SETD5 as a gene, covering its protein structure, what it does inside cells, how having only one working copy, called haploinsufficiency, leads to brain development disorders, why too much SETD5 activity appears in some cancers, and how SETD5 protein levels are controlled inside cells.

• SETD5 encodes a protein in the lysine methyltransferase family, but research has shown it functions primarily as a scaffold — organizing other regulatory proteins — rather than as an active enzyme directly methylating histones.
• The review covers the full range of evidence for SETD5's role in NDD, including mouse model data, human patient studies, and molecular mechanism research available through early 2023.
• It describes how SETD5 protein levels are controlled by the ubiquitin-proteasome system, which is relevant to understanding why haploinsufficiency (having one functional copy) cannot easily be compensated for by the remaining copy.
• The paradox between SETD5 loss causing neurodevelopmental disorder and SETD5 overexpression appearing in multiple cancer types is discussed, with SETD5's roles in each context described separately.

As of its publication in 2023, this is the most comprehensive review of SETD5 as a gene. Families or clinicians who want a single reference covering the biology, the evidence for SETD5 Syndrome, and the state of the research can use this as a starting point.

A patient with SETD5 Syndrome came in with multiple vertebral fractures and significantly below-average bone mineral density for their age. The authors looked back at existing SETD5 literature to see how often bone-related findings had been documented before.

• This is the first published paper formally linking SETD5 to bone fragility.
• The patient had vertebral wedge fractures (compression deformities of the spinal vertebrae) and reduced bone mineral density on DEXA scan.
• Treatment with zoledronic acid, a bone-strengthening medication, improved bone density measurements in this patient.
• The authors of this study suggested bone density evaluation for all patients with SETD5 Syndrome; families may wish to discuss this with their child's care team.

Bone fragility had not been documented in the SETD5 Syndrome literature before 2021. This was the first published report of this association.

Researchers used mouse models to investigate the role of Setd5 in heart development, specifically in the tissue that gives rise to the heart and certain head and neck structures. They observed what happened when Setd5 function was reduced in that tissue.

• Setd5 was shown to be required for normal development of the cardiopharyngeal mesoderm, the precursor tissue for both heart structures and certain facial/neck muscles.
• Setd5 haploinsufficiency was associated with outflow tract defects in the mouse heart, providing a biological explanation for congenital heart defects observed in SETD5 patients.
• This is the first study to provide a specific developmental mechanism connecting SETD5 to cardiac malformations.

Congenital heart defects have been documented in a subset of SETD5 Syndrome patients across published case series, including defects in the walls that separate the chambers of the heart. This study provides a biological reason for why those features occur.

Researchers investigated how the SETD5 protein connects with a gene-regulating complex inside cells called NCoR, which works alongside a protein called HDAC3 that helps control gene activity. They studied how this partnership regulates which genes are turned on or off and how SETD5 protein levels are controlled over time. A cellular differentiation model was used to track these dynamics in detail.

• SETD5 was shown to form a functional complex with NCoR-HDAC3, a major transcriptional co-repressor, where it suppresses the activation of gene-regulatory enhancers.
• When SETD5 leaves or is removed from this complex, the enhancers it was suppressing become active — SETD5 functions as a molecular brake on gene activation.
• SETD5 protein levels are regulated by the APC/C-CDC20 ubiquitin ligase system, which tags SETD5 for controlled degradation at specific times. This controlled degradation is how cells allow genes to turn on in a timed way.
• The study extends the NCoR pathway first described in SETD5 Syndrome research (Deliu et al. 2018) by showing the specific molecular details of how the complex works and is regulated — confirming that SETD5 functions as a scaffold within the co-repressor complex rather than as a direct enzymatic modifier.

This is a molecular biology study with no patient data. Its relevance to SETD5 Syndrome is that it advances understanding of how the SETD5 protein works inside cells. Understanding the normal mechanism is a necessary step in working toward targeted therapies.

A prenatally diagnosed case involving a complex chromosomal rearrangement. The fetus had both a deletion at chromosome region 3p26.3-3p25.3, which includes the SETD5 region, and a duplication at chromosome region 2p25.3-2p25. Cystic hygroma, a fluid-filled sac typically found in the neck, was identified at 13 weeks through ultrasound.

• The fetus had a septated cystic hygroma detected at 13 weeks. Karyotyping and microarray analysis identified an unbalanced translocation of paternal origin.
• The father carried the translocation in balanced form and had a family history of recurrent miscarriages — illustrating that a balanced chromosomal translocation involving the SETD5 region can have different outcomes depending on how it segregates in offspring.
• The deleted region at 3p26.3–3p25.3 (11.6 Mb) contains 65 genes; three — including SETD5 — have high haploinsufficiency scores in the ClinGen gene dosage database.
• This deletion is substantially larger than typical isolated SETD5 deletions or point mutations. Features in this case may reflect the combined loss of multiple genes, not SETD5 alone.

This case is most directly relevant to families whose child has a larger chromosomal deletion involving SETD5 alongside other genes, or families whose prenatal history included cystic hygroma. This involves a complex chromosomal rearrangement affecting multiple genes, so families with isolated SETD5 point mutations should note that the features may reflect losses of several genes in the deleted region, not just SETD5.

Clinicians described a pregnancy where first-trimester ultrasound found a cystic hygroma, a fluid-filled sac typically in the neck area. Standard chromosomal microarray testing came back normal, and a later ultrasound was also normal. Whole exome sequencing, a type of genetic test that reads all the protein-coding genes, later identified a SETD5 frameshift variant as the cause.

• This is among the earliest published prenatal cases in which SETD5 Syndrome was confirmed as the underlying diagnosis after a first-trimester ultrasound finding.
• Standard microarray testing was normal, illustrating that SETD5 point variants and small frameshift variants may not be detected by chromosomal microarray alone — only by sequencing-based approaches.
• The cystic hygroma resolved on follow-up ultrasound; the SETD5 variant was identified only after WES was performed.
• The authors note that cystic hygroma in the first trimester, even with normal microarray results, may warrant further sequencing investigation when the fetus is otherwise structurally normal.

This case shows that some SETD5 variants are not detectable by standard microarray testing and may only be found through exome or genome sequencing. Families who received a prenatal SETD5 diagnosis, or whose child went undiagnosed prenatally despite ultrasound findings, may find the diagnostic path described here useful context.

Clinicians described a 2-year-old girl with a de novo, meaning newly arising, 3p25.3 microdeletion encompassing the SETD5 gene region who developed low-stage neuroblastoma. The authors reviewed existing SETD5 and neuroblastoma research to explore a possible biological connection.

• This is the first published case reporting neuroblastoma in a child with confirmed SETD5 haploinsufficiency.
• The patient presented with classic SETD5/3p25 features including low frontal hairline, synophrys, long eyelashes, epicanthal folds, camptodactyly, delayed psychomotor development, intellectual disability, and agitated behavior.
• The deletion narrowed the critical overlapping 3p25 region to 25 kb, containing only the 3' end of SETD5, reinforcing SETD5 as the single gene responsible for the neurodevelopmental phenotype in 3p25 deletions.
• SETD5-haploinsufficient mice develop neural crest defect-associated features (craniofacial abnormalities, tooth displacement, eye problems) that overlap with features seen in SETD5 patients, suggesting a possible shared biological basis between neurodevelopmental defects and neuroblastoma susceptibility.
• The authors conclude that SETD5 germline deletion may confer shared susceptibility to neurodevelopmental disorders and childhood cancer, though larger studies are needed to confirm this.

This is a single case report and cannot establish that children with SETD5 Syndrome have an elevated risk for neuroblastoma. The published association may be worth mentioning to your child's oncologist or pediatrician if it seems relevant to your child's situation, but one case does not confirm a causal link.

Clinicians described three patients who were clinically suspected of having KBG syndrome but were found through genetic testing to carry pathogenic SETD5 variants instead.

• All three patients had features overlapping with KBG syndrome, reinforcing the documented clinical similarity between the two conditions.
• Genetic testing revealed SETD5 haploinsufficiency rather than ANKRD11 mutations (the gene responsible for KBG syndrome).
• This study provided early clinical evidence for the molecular connection between SETD5 and the KBG syndrome pathway, a link that has since been confirmed at the molecular level by Sashiyama et al. 2025.

If your child was evaluated for KBG syndrome before receiving a SETD5 Syndrome diagnosis, this paper documents that the clinical overlap between the two conditions is recognized in the medical literature. Research advances in either condition may benefit both.

Researchers investigated how the SETD5 protein controls the growth and division of neural cells by regulating ribosomal DNA (rDNA), the genes that produce the cell's protein-building machinery.

• SETD5 was shown to directly control neural cell proliferation through epigenetic regulation of rDNA expression.
• When SETD5 function is reduced, neural cell proliferation is altered, providing a specific cellular mechanism linking SETD5 haploinsufficiency to brain developmental differences.
• The rDNA regulation pathway represents a distinct mechanism from the NCoR pathway identified by Deliu et al. 2018, suggesting SETD5 affects brain development through multiple biological pathways.

This study identifies a specific cellular process affected by having only one working copy of SETD5, specifically how brain cells grow and divide. Understanding these mechanisms is a necessary step toward developing targeted therapies.

A body of research has examined SETD5 in the context of cancer biology. The most prominent studies focus on SETD5 overexpression, meaning too much SETD5 activity, in solid tumors including pancreatic and breast cancers. These studies describe SETD5 behaving like a gene that promotes tumor growth when it is overproduced in cancer cells.

• Wang et al. (2020, Cancer Cell) found that SETD5 is overexpressed in pancreatic cancer and promotes tumor cell survival. This work is in the context of excess SETD5 protein in cancer cells, the opposite of the SETD5 haploinsufficiency (reduced function) that causes SETD5 Syndrome.
• Yang et al. (2020, 2022) found elevated SETD5 expression in breast cancer samples and in cancer cell lines. Again, these studies describe too much SETD5, not too little.
• This apparent paradox (SETD5 loss causes neurodevelopmental differences, while SETD5 overexpression is associated with cancer) is consistent with how many genes involved in development and cell growth behave differently depending on context and cell type.
• There is no published evidence that germline SETD5 haploinsufficiency (the genetic basis of SETD5 Syndrome) predisposes individuals to cancer. The cancer-associated research involves somatic (acquired, not inherited) overexpression in tumor cells.

Families sometimes encounter research linking SETD5 to cancer and wonder what it means. The cancer research involves too much SETD5 activity in tumor cells. That is a different biological situation from SETD5 Syndrome, which involves too little SETD5 activity. There is no established evidence that having a SETD5 Syndrome variant increases cancer risk. Questions about cancer risk in the context of a SETD5 diagnosis are best directed to a clinical geneticist who knows your child's specific variant.