Mendeliome
Gene: HDAC2 Green List (high evidence)Green List (high evidence)
PMID: 27620904 In a large syndromic ID cohort one de novo missense in HDAC2 was identified Gly28Asp (filtered out in gnomad). This individual is also present in DECIPHER where the phenotype listed are: hypotonia, autistic behaviour, delayed speech and language development, developmental regression, hyperactivity, intellectual disability, motor stereotypy, and symptomatic seizures.
PMID: 30806031 Met31Ile identified as de novo in an individual with a phenotype resembling Cornelia de Lange syndrome - severe developmental delay, limb abnormalities, congenital heart defect, cryptorchidism and hypoplastic genitalia, growth retardation, and characteristic craniofacial features. The variant is absent from gnomad. This individual also had a 5.6Mb copy number gain at 15q11.2q13.1 which is associated with a developmental disorder.
PMID: 38753158 An individual clinically diagnosed with Rubenstein Tabi syndrome who had negative genetic testing for known RSTS genes. Phenotype included ID, growth and motor delay, dysmorphisms (synophrys, prominent columella, short philtrum, high nasal root, abnormal ears with prominent antihelix), broad halluces, speech delay, feeding problems and recurrent infections, vertebral anomalies, hypoplasia of corpus callosum, hypermetropia and early puberty. Identified a de novo frameshift p.(K444Lfs*61) in HDAC2 which is an elongation variant. This variant is absent from gnomad but other elongation variants are present with 4-13 hets. The variant was predicted to disrupt the NLS and studies in transfected cells showed protein mislocalisation. HDAC2 protein abundance was also reduced in patient cells, and patient cells showed similar differentially expressed genes to RSTS patients.
The two missense are near each other and are present at or near annotated binding sites in DECIPHER, both very well conserved residues and one of the paper described this region as needed for the catalytic activity of the deacetylase. Borderline amber/green due to lack of functional evidence for the missense variants and the presence of other elongation variants in gnomad (however it is unclear if they also affect the NLS).
Sources: LiteratureCreated: 11 Jun 2026, 3:18 p.m.
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Phenotypes
Neurodevelopmental disorder (MONDO:0700092), HDAC2-related
Publications
Gene: hdac2 has been classified as Green List (High Evidence).
gene: HDAC2 was added gene: HDAC2 was added to Mendeliome. Sources: Literature Mode of inheritance for gene: HDAC2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: HDAC2 were set to 30806031; 27620904; 38753158 Phenotypes for gene: HDAC2 were set to Neurodevelopmental disorder (MONDO:0700092), HDAC2-related Review for gene: HDAC2 was set to GREEN
If promoting or demoting a gene, please provide comments to justify a decision to move it.
Genes included in a Genomics England gene panel for a rare disease category (green list) should fit the criteria A-E outlined below.
These guidelines were developed as a combination of the ClinGen DEFINITIVE evidence for a causal role of the gene in the disease(a), and the Developmental Disorder Genotype-Phenotype (DDG2P) CONFIRMED DD Gene evidence level(b) (please see the original references provided below for full details). These help provide a guideline for expert reviewers when assessing whether a gene should be on the green or the red list of a panel.
A. There are plausible disease-causing mutations(i) within, affecting or encompassing an interpretable functional region(ii) of this gene identified in multiple (>3) unrelated cases/families with the phenotype(iii).
OR
B. There are plausible disease-causing mutations(i) within, affecting or encompassing cis-regulatory elements convincingly affecting the expression of a single gene identified in multiple (>3) unrelated cases/families with the phenotype(iii).
OR
C. As definitions A or B but in 2 or 3 unrelated cases/families with the phenotype, with the addition of convincing bioinformatic or functional evidence of causation e.g. known inborn error of metabolism with mutation in orthologous gene which is known to have the relevant deficient enzymatic activity in other species; existence of an animal model which recapitulates the human phenotype.
AND
D. Evidence indicates that disease-causing mutations follow a Mendelian pattern of causation appropriate for reporting in a diagnostic setting(iv).
AND
E. No convincing evidence exists or has emerged that contradicts the role of the gene in the specified phenotype.
(i)Plausible disease-causing mutations: Recurrent de novo mutations convincingly affecting gene function. Rare, fully-penetrant mutations - relevant genotype never, or very rarely, seen in controls. (ii) Interpretable functional region: ORF in protein coding genes miRNA stem or loop. (iii) Phenotype: the rare disease category, as described in the eligibility statement. (iv) Intermediate penetrance genes should not be included.
It’s assumed that loss-of-function variants in this gene can cause the disease/phenotype unless an exception to this rule is known. We would like to collect information regarding exceptions. An example exception is the PCSK9 gene, where loss-of-function variants are not relevant for a hypercholesterolemia phenotype as they are associated with increased LDL-cholesterol uptake via LDLR (PMID: 25911073).
If a curated set of known-pathogenic variants is available for this gene-phenotype, please contact us at panelapp@genomicsengland.co.uk
We classify loss-of-function variants as those with the following Sequence Ontology (SO) terms:
Term descriptions can be found on the PanelApp homepage and Ensembl.
If you are submitting this evaluation on behalf of a clinical laboratory please indicate whether you report variants in this gene as part of your current diagnostic practice by checking the box
Standardised terms were used to represent the gene-disease mode of inheritance, and were mapped to commonly used terms from the different sources. Below each of the terms is described, along with the equivalent commonly-used terms.
A variant on one allele of this gene can cause the disease, and imprinting has not been implicated.
A variant on the paternally-inherited allele of this gene can cause the disease, if the alternate allele is imprinted (function muted).
A variant on the maternally-inherited allele of this gene can cause the disease, if the alternate allele is imprinted (function muted).
A variant on one allele of this gene can cause the disease. This is the default used for autosomal dominant mode of inheritance where no knowledge of the imprinting status of the gene required to cause the disease is known. Mapped to the following commonly used terms from different sources: autosomal dominant, dominant, AD, DOMINANT.
A variant on both alleles of this gene is required to cause the disease. Mapped to the following commonly used terms from different sources: autosomal recessive, recessive, AR, RECESSIVE.
The disease can be caused by a variant on one or both alleles of this gene. Mapped to the following commonly used terms from different sources: autosomal recessive or autosomal dominant, recessive or dominant, AR/AD, AD/AR, DOMINANT/RECESSIVE, RECESSIVE/DOMINANT.
A variant on one allele of this gene can cause the disease, however a variant on both alleles of this gene can result in a more severe form of the disease/phenotype.
A variant in this gene can cause the disease in males as they have one X-chromosome allele, whereas a variant on both X-chromosome alleles is required to cause the disease in females. Mapped to the following commonly used term from different sources: X-linked recessive.
A variant in this gene can cause the disease in males as they have one X-chromosome allele. A variant on one allele of this gene may also cause the disease in females, though the disease/phenotype may be less severe and may have a later-onset than is seen in males. X-linked inactivation and mosaicism in different tissues complicate whether a female presents with the disease, and can change over their lifetime. This term is the default setting used for X-linked genes, where it is not known definitately whether females require a variant on each allele of this gene in order to be affected. Mapped to the following commonly used terms from different sources: X-linked dominant, x-linked, X-LINKED, X-linked.
The gene is in the mitochondrial genome and variants within this can cause this disease, maternally inherited. Mapped to the following commonly used term from different sources: Mitochondrial.
Mapped to the following commonly used terms from different sources: Unknown, NA, information not provided.
For example, if the mode of inheritance is digenic, please indicate this in the comments and which other gene is involved.