Intellectual disability syndromic and non-syndromic
STR: DIP2B_FRA12A_CGG Amber List (moderate evidence)I don't know
Unsure about the expansions association with disease due to variable phenotypes and possible incomplete penetrance PMID 17236128, 39854091, and 41028987 report 23 unrelated families with heterozygous CGG repeat expansions in the 5′UTR of DIP2B. Sixteen families present with intellectual disability associated with the FRA12A fragile site, while seven families (including two siblings, five ataxia probands, and one dystonia case) exhibit neurodevelopmental disability with progressive movement disorders (chorea, dystonia, ataxia). Functional studies demonstrate reduced DIP2B expression via promoter hypermethylation. Segregation analysis shows segregation from unaffected parents (possibly reduced penetrance) and de novo events. DIP2B expansion OR 2.8 (p=0.04) in ataxia cohort (5/788) vs gnomAD.Created: 29 Oct 2025, 9:04 p.m. | Last Modified: 29 Oct 2025, 9:04 p.m.
Panel Version: 1.397
NM_173602.2:c.-137CGG[X]
All individuals expressing FRA12A had CGG-repeat expansion. The length of the expanded allele in 3 unaffected FRA12A carriers was 650–850 bp. In the two affected patients from 2 families with FRA12A, the length of the expanded allele was ∼1,050-1,150 bp.
70 controls used to determine the "normal" repeat range.
Sources: OtherCreated: 10 Dec 2020, 2:01 p.m.
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes
intellectual disability, FRA12A type MONDO:0007634
Publications
Publications for STR: DIP2B_FRA12A_CGG were set to 17236128
FRA12A was changed to DIP2B_FRA12A_CGG
Str: fra12a has been classified as Amber List (Moderate Evidence).
Str: fra12a has been classified as Amber List (Moderate Evidence).
STR: FRA12A was added STR: FRA12A was added to Intellectual disability syndromic and non-syndromic. Sources: Other 5'UTR tags were added to STR: FRA12A. Mode of inheritance for STR: FRA12A was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted Publications for STR: FRA12A were set to 17236128 Phenotypes for STR: FRA12A were set to Mental retardation, FRA12A type MIM#136630 Review for STR: FRA12A was set to AMBER
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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).
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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.
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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.