Intellectual disability - microarray and sequencing
Gene: NUDT2 Green List (high evidence)The rating of this gene has been updated following NHS Genomic Medicine Service approval.Created: 9 Mar 2022, 3:40 p.m. | Last Modified: 9 Mar 2022, 3:40 p.m.
Panel Version: 3.1510
Comment on list classification: This gene should be promoted to Green at the next GMS panel update (added 'for-review' tag). There are now at least 2 biallelic variants reported in 6 families - 3 of which present GDD and ID, while the remaining had delay but borderline intelligence.Created: 3 Nov 2020, 2:03 p.m. | Last Modified: 3 Nov 2020, 2:03 p.m.
Panel Version: 3.510
Removed 'founder-effect' tag, as the recent publication (PMID: 33058507) identified by Zornitza Stark (Australian Genomics) provides evidence of additional pathogenic variants in the NUDT2 geneCreated: 3 Nov 2020, 1:36 p.m. | Last Modified: 3 Nov 2020, 1:36 p.m.
Panel Version: 3.507
Green List (high evidence)
Three individuals from two additional families reported with a different homozygous variant and ID/polyneuropathy phenotype.Created: 2 Nov 2020, 9:49 a.m. | Last Modified: 2 Nov 2020, 9:49 a.m.
Panel Version: 3.500
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Muscular hypotonia; Global developmental delay; Intellectual disability; Polyneuropathy
Publications
Variants in this GENE are reported as part of current diagnostic practice
Comment on list classification: New gene added by external expert and reviewed by curation team. NUDT2 has been given an amber gene rating (as all reported cases are from the same geographical region) based on the evidence provided by Konstantinos Varvagiannis.Created: 22 Feb 2019, 3:15 p.m.
I don't know
PMID: 27431290 reports briefly on 2 sibs from a consanguineous Saudi family, as part of a cohort of 337 patients investigated for intellectual disability. Both were homozygous for a nonsense NUDT2 mutation [NM_001161.4:c.34C>T or p.Arg12Ter / rs148119952]. The common features included hypotonia, global developmental delay (first words at 2.5 years, sitting at 2-2.5 years,walking achieved by 4 years - valid for both sibs) and intellectual disability. No other candidate variants were found in the exome.
PMID: 30059600 is a further report on 5 individuals from 3 consanguineous families from Saudi Arabia. All presented with low birth weight and height, poor suck, hypotonia, motor and language delay and borderline intelligence. All patients were homozygous for the same nonsense variant (Arg12Ter) which seems to be a founder mutation in Saudi Arabia.
As truncating NUDT2 variants have a combined allele frequency of 0.02% in gnomAD (no homozygotes in the database) the authors comment that most of the other LoF variants observed are in the second - and last - exon of the gene (thus probably escaping NMD) and downstream of its catalytic domain.
As a result this gene can be considered for inclusion in the ID panel probably as amber (single founder mutation - the degree of intellectual disability appears to be more severe in the first report but borderline in the subsequent) or green.
Sources: Literature, Expert ReviewCreated: 21 Nov 2018, 1:41 a.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Muscular hypotonia; Global developmental delay; Intellectual disability
Publications
Tag for-review was removed from gene: NUDT2.
Source Expert Review Green was added to NUDT2. Rating Changed from Amber List (moderate evidence) to Green List (high evidence)
Gene: nudt2 has been classified as Amber List (Moderate Evidence).
Tag founder-effect was removed from gene: NUDT2. Tag for-review tag was added to gene: NUDT2.
Phenotypes for gene: NUDT2 were changed from Muscular hypotonia; Global developmental delay; Intellectual disability; no OMIM number to Muscular hypotonia; Global developmental delay; Intellectual disability; Polyneuropathy; no OMIM number
Publications for gene: NUDT2 were set to 27431290; 30059600
Gene: nudt2 has been classified as Amber List (Moderate Evidence).
Tag founder-effect tag was added to gene: NUDT2.
Phenotypes for gene: NUDT2 were changed from Muscular hypotonia; Global developmental delay; Intellectual disability to Muscular hypotonia; Global developmental delay; Intellectual disability; no OMIM number
gene: NUDT2 was added gene: NUDT2 was added to Intellectual disability. Sources: Literature,Expert Review Mode of inheritance for gene: NUDT2 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: NUDT2 were set to 27431290; 30059600 Phenotypes for gene: NUDT2 were set to Muscular hypotonia; Global developmental delay; Intellectual disability Penetrance for gene: NUDT2 were set to Complete Review for gene: NUDT2 was set to AMBER
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 [email protected]
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.