Is NR4A2 an intellectual developmental disorder?

The condition caused by NR4A2 variants is catalogued internationally as an intellectual developmental disorder. Its official name in OMIM, the reference catalogue for genetic conditions, is “Intellectual developmental disorder with language impairment and early-onset DOPA-responsive dystonia-parkinsonism” (MIM 619911). The definition opens by describing “global developmental delay affecting motor, cognitive, and speech domains apparent in early childhood or infancy”.

ClinGen rates the gene-condition link Definitive, its highest evidence tier, and the panel that made that call is named the Intellectual Disability and Autism Gene Curation Expert Panel. NR4A2 is a Green, diagnostic-grade gene on the intellectual disability panels of both PanelApp Australia and Genomics England.

Across the published literature, intellectual disability or developmental delay is reported in 93 to 100 per cent of individuals. Severity genuinely varies from mild to severe, and no genotype-phenotype correlation has been established. So the literature establishes that cognitive and language impairment is a core, near-universal and lifelong feature of the condition. It does not, and cannot, say where any individual child falls within that range.

The single most efficient link to send someone who has never heard of this gene is the NCBI MedGen entry. It is free, needs no login, sits on a US National Institutes of Health domain, and reproduces the official OMIM definition verbatim. The condition's name on that page leads with “Intellectual developmental disorder with language impairment”, which makes the point before anyone reads a word of body text.

For an Australian reader, the second link worth sending is PanelApp Australia, which lists NR4A2 as a Green, diagnostic-grade gene on the national “Intellectual disability syndromic and non-syndromic” panel.

1. NCBI MedGen. Intellectual developmental disorder with language impairment and early-onset DOPA-responsive dystonia-parkinsonism (IDLDP). Concept ID C5677001, MedGen UID 1805453. Reproduces OMIM #619911.

   The official disorder name is "Intellectual developmental disorder with language impairment and early-onset DOPA-responsive dystonia-parkinsonism (IDLDP)", OMIM phenotype MIM 619911, gene NR4A2 at 2q24.1. The OMIM-sourced definition, tagged "[from OMIM]", characterises it as "global developmental delay affecting motor, cognitive, and speech domains apparent in early childhood or infancy". The HPO feature list on the same page includes global developmental delay, delayed speech and language development, and mild intellectual disability.

   why it counts The disorder's own name begins with the words intellectual developmental disorder. Nobody has to infer it. Free, no login, and on a US National Institutes of Health domain, so it reads as a reference source rather than advocacy material.

2. OMIM #619911. Intellectual developmental disorder with language impairment and early-onset DOPA-responsive dystonia-parkinsonism; IDLDP. Gene NR4A2, OMIM *601828.

   Phenotype MIM number 619911, gene MIM 601828, autosomal dominant inheritance. This is the citation form a paediatrician or assessor will recognise on sight.

   why it counts Cite as OMIM #619911 next to the MedGen link. The OMIM site itself loads normally in a browser but blocks automated tools, so MedGen is the link to hand over.

3. ClinGen Gene-Disease Validity. NR4A2 (HGNC:7981), complex neurodevelopmental disorder (MONDO:0100038), autosomal dominant. Intellectual Disability and Autism Gene Curation Expert Panel, approved 5 May 2021 (SOP8).

   ClinGen classifies the NR4A2 gene-disease relationship as DEFINITIVE, the highest of its six validity tiers. The curating body is named the "Intellectual Disability and Autism Gene Curation Expert Panel". ClinGen's Dosage Sensitivity Working Group separately scores NR4A2 as having sufficient evidence for haploinsufficiency (score 3), curated 27 September 2022.

   why it counts Definitive is the strongest verdict ClinGen issues, so the gene-condition link cannot be dismissed as emerging or speculative. The haploinsufficiency score matters because a frameshift variant works by loss of function, which is precisely the mechanism ClinGen assessed.

4. Orphanet. Developmental delay-language impairment-dopa responsive dystonia-parkinsonism syndrome. ORPHA:660017.

   The European reference nosology names the disorder Developmental delay-language impairment-dopa responsive dystonia-parkinsonism syndrome, cross-referenced to OMIM:619911 and MONDO:0859257. Autosomal dominant, onset in infancy or childhood, prevalence under 1 in 1,000,000 with roughly 15 documented families.

   why it counts A second, independent official catalogue whose disorder name also leads with developmental delay and language impairment. Two separate nosologies agreeing is harder to argue with than one.

5. PanelApp Australia. Panel 250, Intellectual disability syndromic and non-syndromic, v2.43. NR4A2 rated GREEN (confidence level 3), Genetic Health Queensland.

   In Australia's national gene-panel resource, NR4A2 is a Green (diagnostic-grade) gene on the Intellectual disability syndromic and non-syndromic panel, curated by Genetic Health Queensland, for the phenotype Intellectual developmental disorder with language impairment and early-onset DOPA-responsive dystonia-parkinsonism, OMIM:619911.

   why it counts The Australian artefact. An Australian assessor is being shown that Australian diagnostic laboratories list this gene, at the highest confidence rating, on the national intellectual disability panel.

6. Genomics England PanelApp. Intellectual disability panel (Panel 285), v10.60. NHS Genomic Medicine Service.

   NR4A2 is a GREEN (highest confidence) gene on the NHS national Intellectual disability diagnostic panel, monoallelic autosomal inheritance, listed against OMIM:619911. It is also Green on the Early onset or syndromic epilepsy panel (Panel 402) and appears three times as Green on the currently orderable R27 Paediatric disorders super panel.

   why it counts A second national health system reaching the same conclusion. Note the standalone R29 Intellectual disability indication was retired from the NHS test directory in April 2026, so describe it as Green on the Intellectual disability panel, whose genes now feed the orderable R27 super panel.

7. EMBL-EBI Gene2Phenotype. NR4A2-related developmental disorder, record G2P02861, Developmental Disorders (DDG2P) panel, updated 21 January 2025.

   Curated in the Developmental Disorders panel with disease name NR4A2-related developmental disorder, monoallelic autosomal, molecular mechanism loss of function, confidence category STRONG.

   why it counts DDG2P is the curated developmental-disorder gene list built out of the Deciphering Developmental Disorders programme and used as the diagnostic list across UK genomic laboratories.

8. Gene Curation Coalition (GenCC). NR4A2 (HGNC:7981) submissions: 1 Definitive, 3 Strong.

   Four independent curating bodies have submitted NR4A2 gene-disease assertions and none is rated below Strong: ClinGen (Definitive), Labcorp Genetics, Gene2Phenotype and PanelApp Australia (Strong), all autosomal dominant.

   why it counts Shows convergence rather than a single opinion. Four expert bodies across three continents, including a large commercial diagnostic laboratory and the Australian curators.

9. SFARI Gene. NR4A2 human gene record, Simons Foundation Autism Research Initiative.

   NR4A2 holds a SFARI gene score of 1, the top tier, labelled "High Confidence". Genetic category: Rare Single Gene Mutation, Syndromic, Functional. The score rationale cites de novo NR4A2 deletions in unrelated individuals with developmental delay or intellectual disability and language impairment, several also meeting DSM-5 criteria for autism spectrum disorder.

   why it counts Adds the autism dimension at the highest confidence tier from the field's main autism gene database, which matters where a submission also covers autism-related support.

10. NCBI ClinVar. NM_006186.4(NR4A2):c.325dup (p.Gln109fs), Variation ID 985332.

    ClinVar holds 284 NR4A2 records, of which 73 are pathogenic or likely pathogenic and 24 are frameshift variants. 20 of those 24 frameshift variants are classified Pathogenic, Likely pathogenic, or Pathogenic/Likely pathogenic, submitted under neurodevelopmental disorder conditions. c.325dup itself is classified Pathogenic with multiple submitters and no conflicts.

    why it counts Shows this class of variant is not a variant of uncertain significance. Diagnostic laboratories worldwide have independently called NR4A2 truncating variants pathogenic, with agreement between submitters.

These are the clinical cohorts. They overlap, because the later reviews re-count patients from the earlier reports, so they must not be added together. Cite one headline figure and use the primary papers for individual detail.

Where published cases report standardised testing rather than a clinical impression, the scores sit in the intellectual disability or borderline range. These are the individual results, on the same Wechsler instruments a school assessment would use.

• WISC-IV Full Scale IQ 65Male, 8 years · Liang et al. 2025
• WISC-IV Full Scale IQ 57Female, 7 years · Liang et al. 2025
• WISC-IV verbal comprehension 63 (1st percentile), working memory 52 (0.1th percentile), overall below −2 SDChild, 9 years · Ramos et al. 2019
• IQ 77, required special education to learn basic writing and arithmeticMale, tested at 7 years · Jesús et al. 2021

A consistent pattern across the reports is that verbal and language scores fall below non-verbal scores. If a child shows the same profile, it is worth naming, because that gap is what drives classroom communication support.

1. Lévy J, Grotto S, Mignot C, et al. NR4A2 haploinsufficiency is associated with intellectual disability and autism spectrum disorder. Clin Genet. 2018 Aug;94(2):264-268.

   Three patients with de novo 2q24.1 deletions involving NR4A2, two of which delete NR4A2 only. The authors report a neurodevelopmental disorder including language impairment, developmental delay, intellectual disability and/or autism spectrum disorder, and attribute it to NR4A2 haploinsufficiency with high penetrance.

   why it counts The title alone does the work for a lay reader: it names intellectual disability and attributes it to loss of one NR4A2 copy. High penetrance is the key phrase, because it means the disability is the expected outcome rather than a possible one.

2. Reuter MS, Krumbiegel M, Schlüter G, Ekici AB, Reis A, Zweier C. Haploinsufficiency of NR4A2 is associated with a neurodevelopmental phenotype with prominent language impairment. Am J Med Genet A. 2017 Aug;173(8):2231-2234.

   A patient with a de novo 89 kb deletion covering NR4A2 and no other gene, with severe language impairment and mild intellectual disability. Notes NR4A2 is highly expressed in brain regions critical for speech and language.

   why it counts The deletion covers no other gene, which removes the alternative explanation that a neighbour is responsible. This is the paper that isolates the effect to NR4A2 alone.

3. Kaplanis J, Samocha KE, Wiel L, et al. Evidence for 28 genetic disorders discovered by combining healthcare and research data. Nature. 2020;586(7831):757-762.

   A de novo mutation study across 31,058 developmental-disorder parent-offspring trios from the Deciphering Developmental Disorders study, GeneDx and Radboud UMC, identifying 285 significantly associated genes. NR4A2 is one of them, with p = 1.75e-6 across the full cohort and p = 2.64e-7 in the undiagnosed subset.

   why it counts Answers the "is this really established, or just a handful of case reports?" question with statistics. In 31,058 children with developmental disorders, damaging new mutations in NR4A2 turned up far more often than chance allows.

4. gnomAD v4, Broad Institute. NR4A2 (ENSG00000153234) constraint metrics.

   NR4A2 is extremely intolerant of loss of function: pLI = 1.00, LOEUF = 0.094, with 1 observed loss-of-function variant against 50.47 expected across the population database.

   why it counts Population-genetics proof that the variant type matters. Across hundreds of thousands of adults in the general population, essentially nobody carries a broken copy of this gene, because carrying one causes a condition significant enough to be noticed.

5. Simons Searchlight. NR4A2-Related Syndrome gene guide, Simons Foundation.

   States that NR4A2-related syndrome is also called intellectual developmental disorder with language impairment and early-onset DOPA-responsive dystonia-parkinsonism, and lists intellectual disability, developmental delay, learning difficulties and speech and language issues among the core symptoms.

   why it counts Plain English an assessor can read without a genetics background, from a foundation that clinicians and funders take seriously.

My son's variant is NM_006186.4:c.325dup, p.(Gln109ProfsTer3), a de novo frameshift. It is not a novel or uncharacterised change, and it has been reported before.

1. Singh S, Gupta A, Zech M, et al. De novo variants of NR4A2 are associated with neurodevelopmental disorder and epilepsy. Genet Med. 2020 Aug;22(8):1413-1417. See Patient 6.

   Patient 6 carries c.325dupC, p.Q109Pfs*3, the same variant. That child had global developmental delay across all domains, seizures from six months of age, speech and language impairment, motor delay, severe hypotonia, feeding difficulties, facial dysmorphism and sleep-disordered breathing, with MRI showing pontine hypoplasia and ventriculomegaly. He was two years old at the time of the report, so intellectual disability had not yet been formally assessed and he is not described as carrying an ID diagnosis.

   why it counts This is the most specific evidence available, and it answers the question an assessor is most likely to ask: how do you know this child is not one of the mild ones. It is a single published case, so it is a documented precedent rather than a prognosis.

2. NCBI ClinVar. NM_006186.4(NR4A2):c.325dup (p.Gln109fs), Variation ID 985332.

   Classified Pathogenic, with multiple independent submitters and no conflicting interpretations. It is filed under the broad condition name Neurodevelopmental disorder rather than the full OMIM 619911 name, which is a cataloguing convention and not a different diagnosis.

   why it counts Confirms this is not a variant of uncertain significance. Diagnostic laboratories that have never met each other reached the same conclusion about this exact change.

3. Ramos LLP, Monteiro FP, Sampaio LPB, et al. Clin Case Rep. 2019;7(8):1582-1584; and Wirth T, Mariani LL, Bergant G, et al. Mov Disord. 2020;35(5):880-885.

   Both report patients carrying c.326dupA, one base away, with the same predicted loss-of-function mechanism. Ramos records WISC-IV verbal comprehension of 63 and working memory of 52 at age 9. Wirth states that both of their patients had a history of mild intellectual disability in childhood.

   why it counts Worth knowing, but treat it as my own inference from a shared mechanism rather than something those papers claim. They report a neighbouring variant, not this one.

One published individual is a documented precedent, not a forecast. It establishes that this variant has been seen at the more affected end of the range, which is the specific question an assessor tends to ask. It says nothing about how any other child carrying it will develop.

My son also carries an inherited 16p11.2 deletion, so his picture is not NR4A2 alone. Carrying two independent causes of developmental impairment is a recognised and quantified situation, and it argues for more support rather than for attributing everything to one gene. The sources below are the honest version of that argument, including the parts that cut against it.

1. Taylor CM, Smith R, Lehman C, et al. 16p11.2 Recurrent Deletion. GeneReviews. 2009 Sep 22 [updated 2021 Oct 28]. University of Washington, Seattle.

   The standard clinical reference for the roughly 593 kb BP4-BP5 deletion. States that "Most affected individuals do not have intellectual disability (defined as an IQ of <70), but many have below average cognition and learning disabilities in both verbal and nonverbal domains", alongside high base rates of speech, language, motor and seizure involvement.

   why it counts Quote this one honestly and in full. It is the reference an assessor will check, and it does not say the deletion causes intellectual disability on its own.

2. ClinGen Dosage Sensitivity Curation. 16p11.2 recurrent region (proximal, BP4-BP5), ISCA-37400.

   Haploinsufficiency score 3, sufficient evidence for haploinsufficiency. Deletions are associated with proximal 16p11.2 microdeletion syndrome, with developmental delay, motor speech and coordination disorders, language disorders and cognitive deficits.

   why it counts The formal expert-panel statement that losing one copy of this region is, by itself, a sufficient cause of disease. That is the step needed to argue it is an independent second cause rather than an incidental finding.

3. Hanson E, Bernier R, Porche K, et al. The cognitive and behavioral phenotype of the 16p11.2 deletion in a clinically ascertained population. Biol Psychiatry. 2015;77(9):785-93.

   85 deletion carriers against 153 familial controls. Over 90% presented with psychiatric and developmental disorders. Expressive and receptive language disorders in 71% of individuals over 3 years. This is the source of the widely quoted downward IQ shift, measured against family members.

   why it counts The comparison group is family members, which controls for family background. Combined with Zufferey 2012 (2 SD shift) and D'Angelo 2016 (mean 22.1 points across 390 carriers), the defensible statement is a shift of roughly 22 to 27 points, not a single constant.

4. Posey JE, Harel T, Liu P, et al. Resolution of Disease Phenotypes Resulting from Multilocus Genomic Variation. N Engl J Med. 2017;376(1):21-31.

   Of 7,374 consecutive patients referred for clinical exome sequencing, 2,076 received a molecular diagnosis, and 101 of those (4.9%) had diagnoses involving two or more disease loci. Phenotypes in those patients were blended or more complex.

   why it counts The canonical citation that two independent molecular diagnoses in one child is a recognised, quantified phenomenon rather than an argumentative device. Racine 2023 (3.5% in an intellectual disability cohort) and Gimeno 2025 (4.2%) converge on the same range.

5. Girirajan S, Rosenfeld JA, Coe BP, et al. Phenotypic heterogeneity of genomic disorders and rare copy-number variants. N Engl J Med. 2012;367(14):1321-31.

   Across 2,312 children carrying a copy-number variant associated with intellectual disability, 10.1% carried a second large copy-number variant. Children carrying two large copy-number variants of unknown clinical significance were eight times as likely to have developmental delay as controls.

   why it counts Evidence for the two-hit principle. Present it as support for the principle, not as a figure that applies to this particular gene-plus-deletion combination, which no study has examined.

This section exists on purpose. An assessor who finds a hole you did not disclose discounts the whole document, and the fastest way to lose a funding argument is to overstate it.

• This literature describes the condition, not any individual child. Every figure here is a statement about published patients. What establishes a particular child's cognitive and adaptive level is their own assessment, and nothing substitutes for it.
• It is 93 to 100 per cent, not 100 per cent. The largest pooled cohort (Borden 2025, n=32) reports 93 per cent, so a small number of published patients did not have intellectual disability or developmental delay documented. Claiming universality is the easiest way to lose credibility on a checkable point.
• OMIM itself documents mild presentations, in the same paragraph an assessor will read: severity is highly variable, and less severely affected individuals have only mild deficits. The Simons Searchlight registry rates 48 per cent mild. Quote that variability yourself rather than letting someone else find it.
• The gene cannot predict an individual outcome. Published severity spans mild to severe and Singh et al. 2020 found no apparent genotype-phenotype correlation. Do not use this literature to forecast an IQ, a trajectory, or a support level.
• The evidence base is small because the condition is ultra-rare, with roughly 15 documented families on Orphanet. Quote fractions as published rather than bare percentages, and be ready to say the denominator is small because the disorder is rare, not because the finding is uncertain.
• Do not add the cohorts together. Borden 2025, Gabaldón-Albero 2024 and the Simons Searchlight registry re-count many of the same underlying patients. Cite one headline figure and use the primary papers for individual detail.
• For a 16p11.2 deletion, the defensible claim is that it is an independently sufficient cause of developmental impairment with a large average effect on cognition, language, motor coordination and seizure risk. It is not that it causes intellectual disability on its own. GeneReviews says the opposite in plain terms.
• No published study examines NR4A2 together with 16p11.2, and no study measures support hours or funding tiers in children with two diagnoses against one. The dual-diagnosis literature supports blended and more complex presentations, not a specific funding entitlement.
• NR4A2 also carries a separate, unrelated association with late-onset Parkinson disease susceptibility. Anyone searching the gene name may land on that material, so it is worth pre-empting in a line.
• Panel versions, ClinVar counts and PanelApp ratings change over time. Everything on this page was checked on 27 July 2026.

The division of labour matters, and stating it plainly is what makes the rest credible.

• The genetics establishes that the diagnosis is real, definitive and lifelong, and that cognitive and language impairment is intrinsic to the condition rather than an incidental finding.
• The psychologist's assessment establishes this child's actual level of functioning. Nothing on this page substitutes for it. Both limbs are needed: a cognitive measure and a separately administered adaptive measure, with severity graded from the adaptive results rather than from Full Scale IQ alone.
• The school's own records of the adjustments actually delivered are what convert into funding in Australia. Support that is needed but not documented records as a lower level of adjustment and attracts less funding.

A sentence worth including verbatim: the published severity range is mild to severe with no established genotype-phenotype correlation, so the diagnosis establishes that cognitive and language impairment is expected, while the assessment establishes its level in this child.

Nothing here is medical advice, and I am a parent rather than a clinician. It is a reading list with the sources checked, written down so it can be handed over in one link.