KDM6B-Related Neurodevelopmental Disorder: Comprehensive Research Report

Executive summary

KDM6B-related neurodevelopmental disorder (KDM6B-NDD), sometimes called Stolerman syndrome, is a rare Mendelian chromatinopathy caused predominantly by heterozygous loss-of-function or function-impairing variants in KDM6B/JMJD3, an H3K27me2/3 histone demethylase. The best current human dataset comprises 85 individuals carrying 71 likely pathogenic variants. Developmental abnormalities were found in essentially all, with intellectual disability (ID) in 63%, autism spectrum disorder (ASD) in 61%, other behavioral problems in 60%, hypotonia in 57%, and neonatal feeding difficulty or gastroesophageal reflux in 51%. Expression is highly variable; most ID is mild, recognizable facial gestalt is absent, and 11% inherited the variant from a mildly affected or apparently unaffected parent. (rots2024clinicalepigeneticsof pages 85-87, rots2024clinicalepigeneticsof pages 79-82)

Recent 2024 experimental work strengthens the biological model: Kdm6b is required for hippocampal neural-stem-cell maintenance, while brain mosaic knockout disrupts NMDA-receptor-mediated transmission and plasticity and produces cognitive, social, and repetitive-behavior phenotypes in mice. These findings are mechanistically important but do not yet establish a human biomarker or treatment. (brauer2024impactofkdm6b pages 9-10, gil2024chromatinregulatorkdm6b pages 1-5, gil2024chromatinregulatorkdm6b pages 11-14)

Table: This table summarizes the most clinically and mechanistically supported findings for KDM6B-related neurodevelopmental disorder, emphasizing quantified human cohort data and clearly marking areas where evidence is still lacking.

1. Disease information

Definition and identifiers

KDM6B-NDD is a congenital-onset, lifelong neurodevelopmental disorder characterized primarily by developmental delay, variable ID, ASD or other behavioral/psychiatric manifestations, and variably associated neurologic, feeding, growth, and congenital abnormalities. It belongs to the Mendelian disorders of the epigenetic machinery/chromatinopathies.

• OMIM phenotype: 618505, Neurodevelopmental disorder with coarse facies and mild distal skeletal abnormalities.
• Gene: KDM6B, also known as JMJD3; gene OMIM 611577.
• Chromosomal location: 17p13.1.
• Synonyms: KDM6B-related neurodevelopmental disorder; KDM6B-related NDD; Stolerman syndrome; neurodevelopmental disorder with coarse facies and mild distal skeletal abnormalities.
• MONDO, Orphanet, MeSH, ICD-10/ICD-11: a disease-specific identifier/code could not be verified in the retrieved authoritative literature. Until formally mapped, broader codes for genetic neurodevelopmental disorder, developmental delay, ID, or ASD should not be represented as disease-specific identifiers.

The OMIM title derives from the initial 12-person series. Investigators studying the expanded cohort caution that coarse facies and distal skeletal abnormalities are uncommon and that the title may mislead clinicians; KDM6B-related neurodevelopmental disorder is consequently the preferable descriptive name. (stolerman2019geneticvariantsin pages 1-2, rots2024clinicalepigeneticsof pages 85-87)

Evidence provenance

The foundational report was an international, clinician-assembled series of 12 unrelated individuals identified largely by clinical whole-exome sequencing (WES), with phenotypes abstracted from records, photographs, and clinician correspondence. The expanded analysis comprised 85 molecularly selected individuals—73 newly evaluated and the original 12—with detailed data unavailable for 16 research-cohort participants. Thus, the principal evidence is aggregated disease-level research based on individual clinical records, not a population-based EHR study. (stolerman2019geneticvariantsin pages 2-2, rots2024clinicalepigeneticsof pages 79-82)

Foundational abstract quotation: “We have identified a number of de novo alterations in the KDM6B gene via whole exome sequencing (WES) in a cohort of 12 unrelated patients with developmental delay, intellectual disability, dysmorphic facial features, and other clinical findings.” Stolerman et al., American Journal of Medical Genetics A, July 2019, DOI: 10.1002/ajmg.a.61173. (stolerman2019geneticvariantsin pages 1-2)

2. Etiology, risk, protection, and gene–environment interaction

Causal factor

The established cause is a germline heterozygous pathogenic or likely pathogenic KDM6B variant. Most variants arise de novo, but inherited disease occurs. The dominant mechanism is reduced KDM6B function—usually haploinsufficiency or functional loss from truncating or critical-domain missense variants—rather than infection, toxin exposure, or a demonstrated dominant-negative mechanism. In the 85-person cohort, 64/85 (75%) variants were confirmed de novo and nine were inherited. (rots2024clinicalepigeneticsof pages 85-87, rots2024clinicalepigeneticsof pages 79-82)

Genetic risk factors

• Protein-truncating variants, including nonsense and frameshift alleles, are strongly implicated.
• Missense variants require domain-aware interpretation; variants affecting the JmjC catalytic region or core residues of the zinc-containing domain have the strongest functional support.
• Some late truncations escape nonsense-mediated decay but delete the critical zinc-containing domain and still cause functional loss.
• Population constraint supports dosage sensitivity: the expanded analysis reports pLI=1 and LOEUF=0.14; the earlier study reported loss-of-function observed/expected ratio 0.06 (90% CI 0.03–0.14). Missense variation overall is less constrained, making functional/domain evidence especially important. (rots2024clinicalepigeneticsof pages 85-87, stolerman2019geneticvariantsin pages 10-11)

Examples from the initial report include c.2684del, c.3085dup, c.3862_3865del, c.1085_1088del, c.3730G>T, and c.3992A>G (p.Asn1331Ser). These examples should not be treated as recurrent hotspots; the expanded cohort contained 71 different variants. (stolerman2019geneticvariantsin pages 6-7, rots2024clinicalepigeneticsof pages 79-82)

Modifiers and environmental factors

No validated modifier gene, protective allele, environmental risk factor, infectious trigger, toxin, diet, or lifestyle factor has been established. The approximately 3:1 male bias prompted a hypothesis of a female protective effect, but this remains inferential. A severe individual carrying pathogenic variants in both KDM6B and HNRNPU illustrates how a second diagnosis may intensify phenotype, but HNRNPU is not an established general modifier. Authors propose that genetic background and environmental factors contribute to expressivity; no specific gene–environment interaction has been demonstrated. (rots2024clinicalepigeneticsof pages 85-87)

3. Phenotypic spectrum

The most reliable frequencies come from the expanded pathogenic/likely pathogenic cohort; denominators vary by available data. Severe ID was reported in only two individuals, one of whom also had an HNRNPU diagnosis. (rots2024clinicalepigeneticsof pages 79-82)

Neurodevelopmental and behavioral phenotypes

• Developmental delay: 72/77, 94%; speech-language, motor, or global; generally evident in infancy or early childhood. Suggested HPO: HP:0001263 Global developmental delay, HP:0000750 Delayed speech and language development, HP:0001270 Motor delay.
• Neurodevelopmental problems: 66/74, 89% in the table’s age-qualified analysis.
• Intellectual disability: 40/64, 63%; usually mild and variable. HPO: HP:0001249.
• Autism: 46/76, 61%. HPO: HP:0000717 Autism.
• Other behavioral problems: 44/73, 60%, including attention and social/behavioral difficulties. HPO: HP:0000708 Behavioral abnormality, with ADHD/anxiety terms where clinically diagnosed.
• Psychotic disorder: 4/20, 20% among those aged ≥12 years. The denominator is small and enriched by ascertainment; this is a surveillance signal, not a population risk estimate. HPO: HP:0000709 Psychosis. (rots2024clinicalepigeneticsof pages 85-87, rots2024clinicalepigeneticsof pages 79-82)

Neurologic phenotypes

• Hypotonia: 40/70, 57%; occasionally severe enough to prompt muscle biopsy or myopathy-panel testing. HPO: HP:0001252.
• Sleep disturbance: 21/66, 32%. HPO: HP:0002360.
• Movement disorder: 16/67, 24%; gait abnormalities, dystonia-like movement, spasticity, hypertonia, and toe walking. Two improved over time; one required botulinum toxin for spasticity. HPO: HP:0100022, HP:0001257 Spasticity, HP:0002066 Gait abnormality, HP:0001332 Dystonia.
• Seizures: 9/69, 13%. HPO: HP:0001250. EEG abnormalities have been described, but routine EEG is not supported in asymptomatic individuals. (stolerman2019geneticvariantsin pages 8-9, rots2024clinicalepigeneticsof pages 79-82)

Growth, gastrointestinal, and congenital phenotypes

• Postnatal overgrowth: approximately 30%; macrocephaly 26%, increased weight 14%, tall stature 8%, and increased birth weight 10/63 (16%). Most had normal growth and none had short stature in the expanded cohort. Suggested HPO: HP:0000256 Macrocephaly, HP:0000098 Tall stature, HP:0004324 Increased body weight.
• Neonatal feeding difficulty or GERD: 33/65, 51%; severe cases required nasogastric feeding or neonatal intensive care. HPO: HP:0011968 Feeding difficulties, HP:0002020 Gastroesophageal reflux.
• Constipation: 11/61, 18%, sometimes chronic and a major care burden. HPO: HP:0002019.
• Congenital heart disease: 13%; genitourinary anomalies: 10%; cleft lip/palate: 4%. Suggested HPO: HP:0001627 Abnormal heart morphology, HP:0000078 Genitourinary abnormality, HP:0000175 Cleft palate, HP:0410030 Cleft lip.
• Musculoskeletal findings include broad hands/fingers or feet/toes (20%), spinal curvature (13%), toe syndactyly (9%), and short digits (9%). HPO: HP:0001159 Syndactyly, HP:0001165 Brachydactyly, HP:0000928 Vertebral-column abnormality. (rots2024clinicalepigeneticsof pages 79-82)

Dysmorphic features are usually mild and inconsistent—prominent forehead/bridge, broad mouth, large ears, round or coarse face, prognathism, and epicanthal folds were reported—but no diagnostic facial gestalt exists. (stolerman2019geneticvariantsin pages 9-10, rots2024clinicalepigeneticsof pages 85-87)

Functional and quality-of-life effects

Speech, learning, adaptive function, social communication, feeding, mobility, sleep, and bowel management can materially affect daily life. Some individuals require special education and lifelong developmental services. Nevertheless, no disease-specific EQ-5D, SF-36, PROMIS, caregiver-burden, or adaptive-function natural-history dataset was found; per-phenotype quality-of-life estimates are unavailable. (stolerman2019geneticvariantsin pages 8-9, stolerman2019geneticvariantsin pages 8-8, rots2024clinicalepigeneticsof pages 79-82)

4. Genetic and molecular information

Gene and protein

KDM6B/JMJD3 encodes a nuclear chromatin regulator that removes di- and trimethyl groups from lysine 27 of histone H3. The gene has 22 exons in the transcript used in the original report (NM_001080424.1). Functionally important C-terminal regions include the JmjC catalytic domain, helical elements, and a zinc-binding motif required for cofactor interaction and protein stability. (stolerman2019geneticvariantsin pages 6-7, stolerman2019geneticvariantsin pages 2-2)

Suggested annotations include GO:0032454 histone demethylase activity, GO:0071558 histone H3-K27 demethylation, nuclear chromatin, and regulation of transcription. The iron/2-oxoglutarate-dependent JmjC reaction implicates iron(II) and 2-oxoglutarate as biochemical cofactors, but no disease-specific cofactor deficiency has been shown.

Variant interpretation

The initial 2019 variants were conservatively reported as VUS because the gene–disease relationship was new. Subsequent recurrence, de novo enrichment, population constraint, and functional assays established the disorder. Current classification should apply ACMG/AMP criteria with careful attention to de novo status, loss-of-function mechanism, domain location, population frequency, phenotype, and functional data. (stolerman2019geneticvariantsin pages 1-2, rots2024clinicalepigeneticsof pages 85-87)

Functional analysis showed strong loss of function for p.Cys1575Ser, which directly disrupts a zinc-binding cysteine; p.Arg1566Ser and p.Glu1570Gln had moderate effects. Conversely, linker or surface variants with minimal functional effects remained VUS. This demonstrates that not every rare KDM6B missense variant is causal. (rots2024clinicalepigeneticsof pages 85-87)

Pathogenic alleles are expected to be ultra-rare or absent from population databases. Exact gnomAD allele frequencies must be checked by variant and transcript at interpretation time; the cohort sources do not provide a frequency for every allele. Disease-causing variants are usually constitutional germline variants. Somatic KDM6B changes in cancer are outside this disorder’s definition.

Chromosomal abnormalities and epigenetic information

Deletions encompassing KDM6B have been reported, but at least seven described deletions also included neighboring genes, preventing attribution of the full phenotype solely to KDM6B. CMA remains appropriate when a copy-number disorder is suspected. (stolerman2019geneticvariantsin pages 10-11)

KDM6B directly regulates the repressive H3K27me2/3 chromatin state. A clinically validated, disease-specific peripheral-blood DNA-methylation episignature was not established in the retrieved KDM6B literature. Methylation profiling is promising across chromatinopathies but should not currently be presented as a validated KDM6B diagnostic test.

5. Environmental information

No causal environmental exposure, lifestyle behavior, occupational exposure, infectious agent, immune trigger, or nutritional deficiency is recognized. Smoking, alcohol, exercise, and diet have not been linked to penetrance or severity. Standard avoidance of known prenatal neurotoxins is good general health practice but is not KDM6B-specific prevention. The disorder is not infectious or transmissible.

6. Mechanism and pathophysiology

Causal chain

Upstream: germline reduction of KDM6B dosage or catalytic/structural function → abnormal persistence or targeting of repressive H3K27me2/3 and disruption of catalytic-independent protein interactions.

Intermediate: altered developmental transcription in neural progenitors and postmitotic neurons → premature neuronal differentiation and depletion of neural-stem-cell pools, impaired maturation of synaptic gene programs, and altered glutamatergic transmission.

Downstream: disturbed circuit formation and plasticity—particularly hippocampal/dentate-gyrus, cortical, and cerebellar programs → developmental delay, cognitive impairment, ASD/behavioral phenotypes, hypotonia/movement abnormalities, and seizures in a subset. The exact mapping from each cellular defect to each human feature remains incomplete. (brauer2024impactofkdm6b pages 9-10, gil2024chromatinregulatorkdm6b pages 1-5, gil2024chromatinregulatorkdm6b pages 11-14, swahari2019histonedemethylasesin pages 3-4)

Neural differentiation and stem-cell maintenance

KDM6B removes H3K27me3 from bivalent chromatin and facilitates neural-lineage programs; evidence includes cooperation with SMAD3 during TGF-β-dependent differentiation and regulation at promoters and enhancers. Suggested GO terms: neurogenesis, regulation of neuron differentiation, neural stem-cell maintenance, and chromatin organization. Suggested CL terms: CL:0000047 neural stem cell, neural progenitor cell, neuroblast, excitatory neuron, and cerebellar granule neuron. (swahari2019histonedemethylasesin pages 3-4)

A February 2024 mouse preprint used conditional deletion, scRNA-seq, transcriptomics, and CUT&RUN. Embryonic deletion left adult dentate gyri essentially devoid of neural stem cells because of precocious differentiation. Acute adult deletion increased TBR2-positive intermediate progenitors by 28% and neuroblasts by 43%, followed by a 25% reduction in adult neural stem cells at 30 days. Only a subset of downregulated maintenance genes gained promoter H3K27me3, supporting additional catalytic-independent functions. Metabolic expression shifted from glycolytic toward oxidative programs, but no validated human metabolomic signature exists. (gil2024chromatinregulatorkdm6b pages 1-5, gil2024chromatinregulatorkdm6b pages 11-14)

Direct abstract quotation: “Conditional deletion of Kdm6b in embryonic DG precursors results in an adult hippocampus that is essentially devoid of NSCs, and hippocampal-dependent behaviors are defective.” Gil et al., bioRxiv, posted February 2024, DOI: 10.1101/2024.02.20.581302. This was a preprint in the retrieved source and should be weighted accordingly. (gil2024chromatinregulatorkdm6b pages 1-5)

Synaptic function and plasticity

The September 2024 peer-reviewed mosaic knockout study found reduced excitatory postsynaptic-current frequency, impaired NMDA-receptor-mediated transmission and LTP, slower NMDA-current decay, and a shift from NR2A toward NR2B-containing receptors. Proposed downstream nodes include PSD95 and NMDAR localization/composition. Mice showed hyperactivity, repetitive behavior, social deficits, and cognitive impairment. Suggested GO terms: chemical synaptic transmission, regulation of NMDA receptor activity, long-term potentiation, learning or memory, and synapse organization. (brauer2024impactofkdm6b pages 9-10, brauer2024impactofkdm6b pages 1-2)

Direct abstract quotation: “KDM6B mosaic knockout display abnormalities in hippocampal excitatory synaptic transmission decreasing NMDA receptor mediated synaptic transmission and plasticity.” Brauer et al., Scientific Reports, September 2024, DOI: 10.1038/s41598-024-70728-5. (brauer2024impactofkdm6b pages 1-2)

Earlier mouse/cell evidence shows that cerebellar Kdm6b loss impairs late expression of glutamate and GABA receptor subunits, while excitatory-neuron deletion dysregulates VGLUT1/2 and synaptic structure. KDM6B is strongly activity inducible and participates in BDNF transcription and neuronal survival. These mechanisms are plausible contributors, not clinical biomarkers. (brauer2024impactofkdm6b pages 1-2, swahari2019histonedemethylasesin pages 4-6, swahari2019histonedemethylasesin pages 7-9)

Immune, metabolic, and tissue-damage mechanisms

KDM6B regulates inflammatory transcription in several contexts, but chronic inflammation, autoimmunity, immunodeficiency, oxidative injury, fibrosis, or a primary metabolic defect has not been demonstrated in KDM6B-NDD. No disease-specific proteomic, metabolomic, or lipidomic signature has been validated. No human single-cell or spatial-transcriptomic study specific to KDM6B-NDD was identified.

7. Anatomical structures affected

The central nervous system is primary. Human manifestations implicate distributed cortical and subcortical networks; mechanistic evidence is strongest for the hippocampus, especially the dentate gyrus, and for cerebellar granule-neuron maturation. Suggested UBERON terms: UBERON:0000955 brain, UBERON:0002421 hippocampal formation, UBERON:0001885 dentate gyrus, UBERON:0002037 cerebellum, and cerebral cortex. (brauer2024impactofkdm6b pages 9-10, gil2024chromatinregulatorkdm6b pages 1-5)

Secondary systems include gastrointestinal tract, heart, genitourinary tract, craniofacial structures, spine, hands, and feet. No consistent lateralization is reported. At the subcellular level, the principal compartment is the nucleus/chromatin, with downstream involvement of excitatory synapses and postsynaptic densities. Suggested GO cellular components: nucleus, chromatin, synapse, postsynaptic density, and glutamatergic synapse.

8. Temporal development and natural history

Onset is congenital or early pediatric and usually insidious: feeding difficulty, hypotonia, or delayed milestones commonly emerge in infancy, followed by speech, learning, ASD, and behavioral manifestations. The condition is chronic and lifelong, not relapsing-remitting. Most cognitive impairment is mild, but expressivity ranges from subtle learning problems to substantial disability. (rots2024clinicalepigeneticsof pages 85-87, rots2024clinicalepigeneticsof pages 79-82)

No formal stages exist. Some movement abnormalities may improve—two cohort members had resolution—whereas developmental and adaptive vulnerabilities generally persist. Psychosis may emerge in adolescence or adulthood; its observed 20% frequency among 20 participants aged ≥12 years requires replication. Critical intervention windows have not been experimentally defined, although standard neurodevelopmental practice favors prompt early therapy. (rots2024clinicalepigeneticsof pages 85-87, rots2024clinicalepigeneticsof pages 79-82)

9. Inheritance and population

Inheritance is autosomal dominant. De novo occurrence predominates, but 9/85 individuals inherited variants maternally (five) or paternally (four) from mildly affected or apparently unaffected parents. This demonstrates reduced penetrance or very subtle expression and mandates parental molecular testing rather than reliance on reported family history. Expressivity is markedly variable. Anticipation, founder variants, and a systematic role for consanguinity are not established. Germline mosaicism was not quantified, but it remains a residual recurrence possibility after an apparently de novo result. (rots2024clinicalepigeneticsof pages 85-87, rots2024clinicalepigeneticsof pages 79-82)

The approximately 75% male proportion may indicate ascertainment effects or female protection. No ethnic, geographic, or founder enrichment is established. A 2024 Pakistani report of a biallelic in-frame duplication is not sufficient to redefine the well-supported dominant disorder model.

Population prevalence and incidence are unknown. The initial GeneDx search identified 12 affected individuals among 10,619 DD/ID-indication exomes (0.12%); this is a diagnostic-cohort yield, not population prevalence. (stolerman2019geneticvariantsin pages 9-10)

10. Diagnostics

Recommended approach

1. Clinical assessment: developmental, neurologic, behavioral/psychiatric, growth, feeding/GI, congenital anomaly, and three-generation family histories; standardized developmental/IQ and ASD evaluation where indicated.
2. First-line genomic testing: trio WES or WGS is preferred for unexplained syndromic NDD; alternatively use a comprehensive ID/ASD/developmental-delay panel containing KDM6B. Trio testing materially strengthens de novo evidence.
3. Copy-number analysis: CMA remains useful, particularly when WES does not reliably detect CNVs. Genome sequencing may unify SNV/indel and structural-variant detection where validated.
4. Variant confirmation and segregation: orthogonal confirmation according to laboratory policy and parental testing. Interpret against the clinically relevant transcript and current ClinVar/gnomAD evidence.
5. Phenotype-driven tests: MRI for focal neurologic signs, regression, abnormal head growth, or seizures; EEG for suspected seizures; swallow/feeding assessment, GI evaluation, echocardiography, renal imaging, ophthalmology, or orthopedic evaluation only when clinically indicated.

The original diagnostic workups used WES, CMA, Fragile-X analysis, neurodevelopmental panels, and metabolic screening. One patient was tested for RAI1/Smith–Magenis syndrome, illustrating phenotypic overlap. The broad and mild dysmorphism means molecular testing—not facial recognition—is decisive. (stolerman2019geneticvariantsin pages 9-10, stolerman2019geneticvariantsin pages 6-7, stolerman2019geneticvariantsin pages 8-9, rots2024clinicalepigeneticsof pages 85-87)

Karyotyping and FISH are not routine unless a rearrangement is suspected. Mitochondrial, repeat-expansion, biopsy, proteomic, metabolomic, or liquid-biopsy testing has no established KDM6B-specific role. RNA sequencing may eventually clarify splice or expression VUS, but no validated disease-specific assay was found. A negative methylation assay cannot currently exclude KDM6B-NDD.

Differential diagnosis

The broad differential includes other chromatinopathies and syndromic NDDs, particularly KDM6A-related Kabuki syndrome, KDM2B-related NDD, CHD8-related NDD, SETD1A-related NDD, Kleefstra syndrome/EHMT1, Wiedemann–Steiner syndrome/KMT2A, Coffin–Siris/BAF-complex disorders, DNMT3A-related Tatton-Brown–Rahman syndrome, NSD1-related Sotos syndrome, and EZH2-related Weaver syndrome. RAI1-related Smith–Magenis syndrome, Fragile X syndrome, CNV disorders, and primary neuromuscular disease may be considered according to sleep/behavior, overgrowth, dysmorphism, hypotonia, or movement presentation. Broad sequencing is more efficient than serial phenotype-driven single-gene testing.

Screening

KDM6B-NDD is not part of newborn screening. Population carrier screening is inappropriate for a predominantly de novo dominant condition. Cascade testing is appropriate when a familial pathogenic variant is identified. Prenatal or preimplantation testing is technically possible once the familial variant is known, after counseling regarding variable expressivity and reduced penetrance.

11. Outcome and prognosis

No disease-specific survival rate, mortality rate, or life-expectancy estimate exists. Available reports do not indicate a characteristic degenerative or fatal course, but adult ascertainment is limited. Prognosis is driven principally by cognitive/adaptive level, communication, ASD/behavioral or psychiatric burden, seizures, movement impairment, feeding/GI morbidity, and congenital anomalies. (rots2024clinicalepigeneticsof pages 85-87, rots2024clinicalepigeneticsof pages 79-82)

Most reported ID is mild, and some movement abnormalities improve, but full neurodevelopmental “recovery” should not be expected. Speech, occupational, educational, and behavioral interventions may improve function without correcting the molecular cause. No prognostic biomarker or reliable genotype–phenotype correlation has been identified. (stolerman2019geneticvariantsin pages 8-8, rots2024clinicalepigeneticsof pages 85-87)

12. Treatment and current applications

There is no approved disease-modifying, gene, RNA, cell, or targeted epigenetic therapy. Current real-world care is individualized and multidisciplinary:

• early developmental intervention; speech-language, occupational, and physical therapy; augmentative communication and special education as needed;
• evidence-based ASD, ADHD, anxiety, sleep, or psychosis care through developmental pediatrics/psychiatry;
• standard antiseizure treatment for epilepsy;
• feeding therapy, nutrition support, reflux treatment, and constipation management;
• PT/orthopedics/rehabilitation for hypotonia, gait, contracture, scoliosis, or spasticity; botulinum toxin helped one reported patient’s spasticity;
• routine management of cardiac, genitourinary, palatal, or other congenital anomalies. (stolerman2019geneticvariantsin pages 8-9, stolerman2019geneticvariantsin pages 8-8, rots2024clinicalepigeneticsof pages 85-87, rots2024clinicalepigeneticsof pages 79-82)

Suggested NCIT intervention concepts include Speech Therapy, Occupational Therapy, Physical Therapy, Behavioral Therapy, Special Education, Anticonvulsant Therapy, Nutritional Support, and Botulinum Toxin Therapy. No KDM6B-specific pharmacogenomic guidance or response-rate evidence exists.

Although epigenetic enzymes are pharmacologically tractable, inhibiting KDM6B would be mechanistically concerning in a loss-of-function disorder. Results from other chromatinopathies cannot be directly translated, and broad prenatal/postnatal chromatin manipulation may have cell- and developmental-stage-specific toxicity.

Trials and registries

No interventional KDM6B-specific trial was identified. Simons Searchlight, NCT01238250, explicitly enrolls people with pathogenic/likely pathogenic KDM6B variants. It is a recruiting, prospective, family-based observational registry collecting annual medical, behavioral, learning, developmental, and biospecimen data; it is not a treatment trial. ClinicalTrials.gov: NCT01238250. (NCT01238250 chunk 1, NCT01238250 chunk 2)

13. Prevention

Primary prevention through lifestyle, vaccination, or environmental modification is unavailable. Secondary/tertiary prevention consists of timely molecular diagnosis, early developmental intervention, seizure recognition, feeding and aspiration assessment when indicated, constipation treatment, orthopedic monitoring, and age-appropriate behavioral/psychiatric surveillance. (rots2024clinicalepigeneticsof pages 85-87, rots2024clinicalepigeneticsof pages 79-82)

Genetic counseling should explain dominant inheritance, the predominance of de novo variants, variable expression, and apparently unaffected transmitting parents. For an affected heterozygous individual, each pregnancy has a theoretical 50% transmission probability, but phenotype cannot be predicted reliably. For parents negative in blood after a de novo diagnosis, recurrence is low but not zero because of possible germline mosaicism. Prenatal diagnosis and PGT-M are options when the familial variant is known.

14. Other species and natural disease

No naturally occurring veterinary syndrome confidently equivalent to human KDM6B-NDD was identified, and there is no zoonotic potential or cross-species transmission. Orthologous Kdm6b is evolutionarily conserved in mouse, and functional conservation is also exploited in Drosophila assays. Species taxon suggestions are Homo sapiens NCBI Taxon 9606, Mus musculus 10090, Drosophila melanogaster 7227, and Danio rerio 7955. Exact ortholog NCBI Gene and breed-ontology identifiers should be retrieved from their live databases before knowledge-base ingestion.

15. Model organisms and advanced technologies

Mouse models

• Constitutive knockout: complete loss is neonatal/embryonic lethal because of respiratory-network deficits, limiting its fidelity for viable heterozygous human disease.
• Heterozygous models: reproduce hyperactivity and social/cognitive abnormalities but may vary by sex and background.
• Conditional neural-stem-cell deletion: demonstrates premature differentiation, failure to establish/maintain dentate-gyrus stem cells, and hippocampal behavioral deficits. scRNA-seq, bulk transcriptomics, and CUT&RUN provide cell-state and chromatin evidence. (gil2024chromatinregulatorkdm6b pages 1-5, gil2024chromatinregulatorkdm6b pages 11-14)
• Postnatal CRISPR mosaic brain knockout: produces repetitive behavior, social and cognitive deficits, and NMDAR/LTP abnormalities. Limitations include broad, non-cell-specific mosaic targeting and incomplete knockout. (brauer2024impactofkdm6b pages 9-10, brauer2024impactofkdm6b pages 1-2)
• Cerebellar granule-neuron conditional knockout: impairs late maturation and synaptic receptor-gene programs while early neuronal markers are relatively preserved. (swahari2019histonedemethylasesin pages 4-6, swahari2019histonedemethylasesin pages 7-9)

Drosophila and cellular systems

Drosophila gain-of-function assays have been useful for discriminating damaging zinc-domain variants from linker/surface VUS. Their limitation is that overexpression may not reproduce human heterozygous haploinsufficiency, and the assay may miss N-terminal interaction defects. Human patient-derived iPSC neurons or organoids would offer higher translational relevance, but no mature KDM6B-NDD iPSC/organoid platform was identified in the retrieved evidence. (rots2024clinicalepigeneticsof pages 85-87)

2023–2024 developments and expert interpretation

1. The expanded 85-person analysis replaced a narrow dysmorphology-centered picture with a genotype-first spectrum dominated by developmental delay, mild ID, ASD, behavioral problems, hypotonia, and feeding/GI concerns. It also established inherited disease and highlighted adolescent psychosis surveillance. (rots2024clinicalepigeneticsof pages 85-87, rots2024clinicalepigeneticsof pages 79-82)
2. The 2024 dentate-gyrus study connected KDM6B to neural-stem-cell maintenance using scRNA-seq and CUT&RUN and suggested both demethylase-dependent and independent functions. (gil2024chromatinregulatorkdm6b pages 1-5, gil2024chromatinregulatorkdm6b pages 11-14)
3. The 2024 mosaic knockout study provided peer-reviewed electrophysiologic evidence linking KDM6B loss to NMDAR composition, LTP, cognition, and ASD-like behaviors. (brauer2024impactofkdm6b pages 9-10, brauer2024impactofkdm6b pages 1-2)
4. Experts caution that domain location alone is insufficient for missense classification; functional evidence showed several presumed damaging linker variants had minimal effects and should remain VUS. (rots2024clinicalepigeneticsof pages 85-87)

Evidence limitations and knowledge-base cautions

The disorder remains underascertained and recently defined. Frequencies are referral-cohort estimates with variable denominators, not population risks. Adult natural history, life expectancy, quantitative quality of life, penetrance, sex effects, and variant-specific prognosis are unresolved. No validated KDM6B blood episignature, fluid biomarker, human single-cell atlas, spatial transcriptomic dataset, disease-specific treatment trial, or proven protective factor was identified. Mouse behavioral findings should be annotated as model evidence rather than human clinical manifestations. Finally, the OMIM phenotype name should be retained as an identifier-linked synonym but not used to imply that coarse facies or distal skeletal abnormalities are obligatory.

References

1. (rots2024clinicalepigeneticsof pages 85-87): Dmitrijs Rots. Clinical epigenetics of mendelian neurodevelopmental disorders. ArXiv, Nov 2024. URL: https://doi.org/10.54195/9789493296831, doi:10.54195/9789493296831. This article has 0 citations.

2. (rots2024clinicalepigeneticsof pages 79-82): Dmitrijs Rots. Clinical epigenetics of mendelian neurodevelopmental disorders. ArXiv, Nov 2024. URL: https://doi.org/10.54195/9789493296831, doi:10.54195/9789493296831. This article has 0 citations.

3. (brauer2024impactofkdm6b pages 9-10): Bastian Brauer, Carlos Ancatén-González, Constanza Ahumada-Marchant, Rodrigo C. Meza, Nicolas Merino-Veliz, Gino Nardocci, Lorena Varela-Nallar, Gloria Arriagada, Andrés E. Chávez, and Fernando J. Bustos. Impact of kdm6b mosaic brain knockout on synaptic function and behavior. Scientific Reports, Sep 2024. URL: https://doi.org/10.1038/s41598-024-70728-5, doi:10.1038/s41598-024-70728-5. This article has 9 citations and is from a peer-reviewed journal.

4. (gil2024chromatinregulatorkdm6b pages 1-5): Eugene Gil, Sung Jun Hong, David Wu, Dae Hwi Park, Ryan N. Delgado, Martina Malatesta, Sajad Hamid Ahanger, Karin Lin, Saul Villeda, and Daniel A. Lim. Chromatin regulator kdm6b is required for the establishment and maintenance of neural stem cells in mouse hippocampus. bioRxiv, Feb 2024. URL: https://doi.org/10.1101/2024.02.20.581302, doi:10.1101/2024.02.20.581302. This article has 4 citations.

5. (gil2024chromatinregulatorkdm6b pages 11-14): Eugene Gil, Sung Jun Hong, David Wu, Dae Hwi Park, Ryan N. Delgado, Martina Malatesta, Sajad Hamid Ahanger, Karin Lin, Saul Villeda, and Daniel A. Lim. Chromatin regulator kdm6b is required for the establishment and maintenance of neural stem cells in mouse hippocampus. bioRxiv, Feb 2024. URL: https://doi.org/10.1101/2024.02.20.581302, doi:10.1101/2024.02.20.581302. This article has 4 citations.

6. (stolerman2019geneticvariantsin pages 1-2): Elliot S. Stolerman, Elizabeth Francisco, Jennifer L. Stallworth, Julie R. Jones, Kristin G. Monaghan, Jennifer Keller‐Ramey, Richard Person, Ingrid M. Wentzensen, Kirsty McWalter, Boris Keren, Benedicte Heron, Caroline Nava, Delphine Heron, Katherine Kim, Barbara Burton, Fatima Al‐Musafri, Lauren O'Grady, Inderneel Sahai, Luis F. Escobar, Marije Meuwissen, Edwin Reyniers, Frank Kooy, Yves Lacassie, Meral Gunay‐Aygun, Krista Sondergaard Schatz, Ron Hochstenbach, Petra J.G. Zwijnenburg, Quinten Waisfisz, Marjon van Slegtenhorst, Grazia M.S. Mancini, and Raymond J. Louie. Genetic variants in the kdm6b gene are associated with neurodevelopmental delays and dysmorphic features. American Journal of Medical Genetics Part A, 179:1276-1286, Jul 2019. URL: https://doi.org/10.1002/ajmg.a.61173, doi:10.1002/ajmg.a.61173. This article has 59 citations.

7. (stolerman2019geneticvariantsin pages 10-11): Elliot S. Stolerman, Elizabeth Francisco, Jennifer L. Stallworth, Julie R. Jones, Kristin G. Monaghan, Jennifer Keller‐Ramey, Richard Person, Ingrid M. Wentzensen, Kirsty McWalter, Boris Keren, Benedicte Heron, Caroline Nava, Delphine Heron, Katherine Kim, Barbara Burton, Fatima Al‐Musafri, Lauren O'Grady, Inderneel Sahai, Luis F. Escobar, Marije Meuwissen, Edwin Reyniers, Frank Kooy, Yves Lacassie, Meral Gunay‐Aygun, Krista Sondergaard Schatz, Ron Hochstenbach, Petra J.G. Zwijnenburg, Quinten Waisfisz, Marjon van Slegtenhorst, Grazia M.S. Mancini, and Raymond J. Louie. Genetic variants in the kdm6b gene are associated with neurodevelopmental delays and dysmorphic features. American Journal of Medical Genetics Part A, 179:1276-1286, Jul 2019. URL: https://doi.org/10.1002/ajmg.a.61173, doi:10.1002/ajmg.a.61173. This article has 59 citations.

8. (stolerman2019geneticvariantsin pages 2-2): Elliot S. Stolerman, Elizabeth Francisco, Jennifer L. Stallworth, Julie R. Jones, Kristin G. Monaghan, Jennifer Keller‐Ramey, Richard Person, Ingrid M. Wentzensen, Kirsty McWalter, Boris Keren, Benedicte Heron, Caroline Nava, Delphine Heron, Katherine Kim, Barbara Burton, Fatima Al‐Musafri, Lauren O'Grady, Inderneel Sahai, Luis F. Escobar, Marije Meuwissen, Edwin Reyniers, Frank Kooy, Yves Lacassie, Meral Gunay‐Aygun, Krista Sondergaard Schatz, Ron Hochstenbach, Petra J.G. Zwijnenburg, Quinten Waisfisz, Marjon van Slegtenhorst, Grazia M.S. Mancini, and Raymond J. Louie. Genetic variants in the kdm6b gene are associated with neurodevelopmental delays and dysmorphic features. American Journal of Medical Genetics Part A, 179:1276-1286, Jul 2019. URL: https://doi.org/10.1002/ajmg.a.61173, doi:10.1002/ajmg.a.61173. This article has 59 citations.

9. (swahari2019histonedemethylasesin pages 3-4): Vijay Swahari and Anne E West. Histone demethylases in neuronal differentiation, plasticity, and disease. Current Opinion in Neurobiology, 59:9-15, Dec 2019. URL: https://doi.org/10.1016/j.conb.2019.02.009, doi:10.1016/j.conb.2019.02.009. This article has 45 citations and is from a peer-reviewed journal.

10. (brauer2024impactofkdm6b pages 1-2): Bastian Brauer, Carlos Ancatén-González, Constanza Ahumada-Marchant, Rodrigo C. Meza, Nicolas Merino-Veliz, Gino Nardocci, Lorena Varela-Nallar, Gloria Arriagada, Andrés E. Chávez, and Fernando J. Bustos. Impact of kdm6b mosaic brain knockout on synaptic function and behavior. Scientific Reports, Sep 2024. URL: https://doi.org/10.1038/s41598-024-70728-5, doi:10.1038/s41598-024-70728-5. This article has 9 citations and is from a peer-reviewed journal.

11. (stolerman2019geneticvariantsin pages 8-9): Elliot S. Stolerman, Elizabeth Francisco, Jennifer L. Stallworth, Julie R. Jones, Kristin G. Monaghan, Jennifer Keller‐Ramey, Richard Person, Ingrid M. Wentzensen, Kirsty McWalter, Boris Keren, Benedicte Heron, Caroline Nava, Delphine Heron, Katherine Kim, Barbara Burton, Fatima Al‐Musafri, Lauren O'Grady, Inderneel Sahai, Luis F. Escobar, Marije Meuwissen, Edwin Reyniers, Frank Kooy, Yves Lacassie, Meral Gunay‐Aygun, Krista Sondergaard Schatz, Ron Hochstenbach, Petra J.G. Zwijnenburg, Quinten Waisfisz, Marjon van Slegtenhorst, Grazia M.S. Mancini, and Raymond J. Louie. Genetic variants in the kdm6b gene are associated with neurodevelopmental delays and dysmorphic features. American Journal of Medical Genetics Part A, 179:1276-1286, Jul 2019. URL: https://doi.org/10.1002/ajmg.a.61173, doi:10.1002/ajmg.a.61173. This article has 59 citations.

12. (stolerman2019geneticvariantsin pages 6-7): Elliot S. Stolerman, Elizabeth Francisco, Jennifer L. Stallworth, Julie R. Jones, Kristin G. Monaghan, Jennifer Keller‐Ramey, Richard Person, Ingrid M. Wentzensen, Kirsty McWalter, Boris Keren, Benedicte Heron, Caroline Nava, Delphine Heron, Katherine Kim, Barbara Burton, Fatima Al‐Musafri, Lauren O'Grady, Inderneel Sahai, Luis F. Escobar, Marije Meuwissen, Edwin Reyniers, Frank Kooy, Yves Lacassie, Meral Gunay‐Aygun, Krista Sondergaard Schatz, Ron Hochstenbach, Petra J.G. Zwijnenburg, Quinten Waisfisz, Marjon van Slegtenhorst, Grazia M.S. Mancini, and Raymond J. Louie. Genetic variants in the kdm6b gene are associated with neurodevelopmental delays and dysmorphic features. American Journal of Medical Genetics Part A, 179:1276-1286, Jul 2019. URL: https://doi.org/10.1002/ajmg.a.61173, doi:10.1002/ajmg.a.61173. This article has 59 citations.

13. (stolerman2019geneticvariantsin pages 9-10): Elliot S. Stolerman, Elizabeth Francisco, Jennifer L. Stallworth, Julie R. Jones, Kristin G. Monaghan, Jennifer Keller‐Ramey, Richard Person, Ingrid M. Wentzensen, Kirsty McWalter, Boris Keren, Benedicte Heron, Caroline Nava, Delphine Heron, Katherine Kim, Barbara Burton, Fatima Al‐Musafri, Lauren O'Grady, Inderneel Sahai, Luis F. Escobar, Marije Meuwissen, Edwin Reyniers, Frank Kooy, Yves Lacassie, Meral Gunay‐Aygun, Krista Sondergaard Schatz, Ron Hochstenbach, Petra J.G. Zwijnenburg, Quinten Waisfisz, Marjon van Slegtenhorst, Grazia M.S. Mancini, and Raymond J. Louie. Genetic variants in the kdm6b gene are associated with neurodevelopmental delays and dysmorphic features. American Journal of Medical Genetics Part A, 179:1276-1286, Jul 2019. URL: https://doi.org/10.1002/ajmg.a.61173, doi:10.1002/ajmg.a.61173. This article has 59 citations.

14. (jaarsveld2023delineationofa pages 6-8): Richard H. van Jaarsveld, Jack Reilly, Marie-Claire Cornips, Michael A. Hadders, Emanuele Agolini, Priyanka Ahimaz, Kwame Anyane-Yeboa, Severine Audebert Bellanger, Ellen van Binsbergen, Marie-Jose van den Boogaard, Elise Brischoux-Boucher, Raymond C. Caylor, Andrea Ciolfi, Ton A.J. van Essen, Paolo Fontana, Saskia Hopman, Maria Iascone, Margaret M. Javier, Erik-Jan Kamsteeg, Jennifer Kerkhof, Jun Kido, Hyung-Goo Kim, Tjitske Kleefstra, Fortunato Lonardo, Abbe Lai, Dorit Lev, Michael A. Levy, M.E. Suzanne Lewis, Angie Lichty, Marcel M.A.M. Mannens, Naomichi Matsumoto, Idit Maya, Haley McConkey, Andre Megarbane, Vincent Michaud, Evelina Miele, Marcello Niceta, Antonio Novelli, Roberta Onesimo, Rolph Pfundt, Bernt Popp, Eloise Prijoles, Raissa Relator, Sylvia Redon, Dmitrijs Rots, Karen Rouault, Ken Saida, Jolanda Schieving, Marco Tartaglia, Romano Tenconi, Kevin Uguen, Nienke Verbeek, Christopher A. Walsh, Keren Yosovich, Christopher J. Yuskaitis, Giuseppe Zampino, Bekim Sadikovic, Mariëlle Alders, and Renske Oegema. Delineation of a kdm2b-related neurodevelopmental disorder and its associated dna methylation signature. Genetics in Medicine, 25:49-62, Jan 2023. URL: https://doi.org/10.1016/j.gim.2022.09.006, doi:10.1016/j.gim.2022.09.006. This article has 40 citations and is from a highest quality peer-reviewed journal.

15. (stolerman2019geneticvariantsin pages 8-8): Elliot S. Stolerman, Elizabeth Francisco, Jennifer L. Stallworth, Julie R. Jones, Kristin G. Monaghan, Jennifer Keller‐Ramey, Richard Person, Ingrid M. Wentzensen, Kirsty McWalter, Boris Keren, Benedicte Heron, Caroline Nava, Delphine Heron, Katherine Kim, Barbara Burton, Fatima Al‐Musafri, Lauren O'Grady, Inderneel Sahai, Luis F. Escobar, Marije Meuwissen, Edwin Reyniers, Frank Kooy, Yves Lacassie, Meral Gunay‐Aygun, Krista Sondergaard Schatz, Ron Hochstenbach, Petra J.G. Zwijnenburg, Quinten Waisfisz, Marjon van Slegtenhorst, Grazia M.S. Mancini, and Raymond J. Louie. Genetic variants in the kdm6b gene are associated with neurodevelopmental delays and dysmorphic features. American Journal of Medical Genetics Part A, 179:1276-1286, Jul 2019. URL: https://doi.org/10.1002/ajmg.a.61173, doi:10.1002/ajmg.a.61173. This article has 59 citations.

16. (NCT01238250 chunk 1): Online Study of People Who Have Genetic Changes and Features of Autism: Simons Searchlight. Simons Searchlight. 2010. ClinicalTrials.gov Identifier: NCT01238250

17. (NCT01238250 chunk 2): Online Study of People Who Have Genetic Changes and Features of Autism: Simons Searchlight. Simons Searchlight. 2010. ClinicalTrials.gov Identifier: NCT01238250

18. (swahari2019histonedemethylasesin pages 4-6): Vijay Swahari and Anne E West. Histone demethylases in neuronal differentiation, plasticity, and disease. Current Opinion in Neurobiology, 59:9-15, Dec 2019. URL: https://doi.org/10.1016/j.conb.2019.02.009, doi:10.1016/j.conb.2019.02.009. This article has 45 citations and is from a peer-reviewed journal.

19. (swahari2019histonedemethylasesin pages 7-9): Vijay Swahari and Anne E West. Histone demethylases in neuronal differentiation, plasticity, and disease. Current Opinion in Neurobiology, 59:9-15, Dec 2019. URL: https://doi.org/10.1016/j.conb.2019.02.009, doi:10.1016/j.conb.2019.02.009. This article has 45 citations and is from a peer-reviewed journal.

Artifacts

• Edison artifact artifact-00

Reference Validation

Checked with linkml-reference-validator 0.2.1.

All extracted references resolved successfully.