Intellectual disability syndromic and non-syndromic
Gene: CAPRIN1 Green List (high evidence)I don't know
Two individuals reported with the same de novo c.1535C > T (p.Pro512Leu) variant and a progressive course.Created: 10 Dec 2023, 6:26 a.m. | Last Modified: 10 Dec 2023, 6:26 a.m.
Panel Version: 0.5647
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes
Neurodegeneration, childhood-onset, with cerebellar ataxia and cognitive decline, MIM# 620636
Publications
Green List (high evidence)
A cohort of 12 individuals harboring pathogenic CAPRIN1 variants is described in a recent report by Pavinato et al (2022 - PMID: 35979925).
DD, impaired speech/language development (100%), ID (83%), ASD (67%) and seizures (33%) are part of the phenotype (details below).
Enrichment for de novo LGD but also missense variants has also been demonstrated upon meta-analysis of different cohorts of 40,853 individuals with ID (N=31,625) or ASD (N=9,228) as discussed by Jia et al (2022 - PMID: 35977029).
Role of the gene:
Evidence supports among others, a role for CAPRIN1 in formation RNA-protein (stress) granules through interaction with other relevant proteins (e.g. G3BP1/2, FMRP) and regulation of gene expression (Pavinato et al - PMID: 35979925, Jia et al - PMID: 35977029).
Jia et al further demonstrated significant reduction of stress granule formation in CAPRIN1 KO HeLa lines.
Following generation of CAPRIN1+/- hiPSC line using CRISPR/Cas9 and differentiation into cortical neurons, Pavinato et al noted, altered neuronal structure, abnormal firing properties as well as increased neuronal degeneration possibly linked to presence of increased Ca+2 signals and increase in reactive oxygen species (ROS). Global de novo protein synthesis in neurons appeared to be impaired.
Variant type and inheritance :
All individuals reported by Paviato et al harbored pLoF (nonsense, frameshift, splicing and a synonymous variant resulting in abnormal splicing) variants. In most cases variants occurred de novo with the exception of 2 subjects having inherited pLoF variants from their affected/unaffected parent. Expressive variability, reduced penetrance and possibility of - a yet to be proven - sex bias are discussed (9M/3F).
Missense variants and enrichment for dn missense SNVs have also been shown in large cohorts. The impact of p.I373K has been studied.
Variant effect:
pLoF : Pavinato et al demonstrated reduced mRNA and protein levels for the truncating variants, and out-of frame exon skipping for a variant affecting splice donor site and a further SNV affecting the last nucleotide of ex8.
Missense SNVs : p.I373K abolished interaction with G3BP1/2 and disrupted stress granule formation in the study by Jia et al demonstrating a role of stress granules in pathogenesis of neurodevelopmental disorders.
Animal model:
As discussed by Pavinato et al abnormal neuronal structure and firing properties are observed in htz mouse models. Htz mice display features of ASD, difficulties in reversal learning (for ID), sporadic occurrence of seizures. Hearing impairment (as in 2-3 individuals described) due to reduced protection from noise exposure was reported in an ear-conditional ko model.
The report by Pavinato et al is summarized below.
For the study by Jia et al a summary can by found under the review of UBAP2L.
Reports of individuals in the context of larger cohorts were not here reviewed (eg. DDD study 2017, PMID: 28135719 || Ruzzo et al 2019, PMID: 31398340 || Fu et al 2021, https://doi.org/10.1101/2021.12.20.21267194).
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Pavinato et al (2022 - PMID: 35979925) describe the phenotype associated with heterozygous CAPRIN1 pathogenic variants.
Overlapping features incl. impaired speech/language development (100%), ID (83%), ASD (67%), ADHD (82%), seizures (33% or 4/12 : absence seizures in 2, infantile spasms with absence epilepsy, secondary generalized epileptic seizures during sleep). Respiratory problems (50%), limb/skeletal anomalies (50%), feeding difficulties (33%), mild hearing hearing impairment (in 2 or 3). There was no evident dysmorphism, despite few recurrent features.
CAPRIN1 encodes cell cycle-associated protein 1. As the authors discuss, the gene is ubiquitously expressed with high expression in brain. The protein is known to interact with other RNA-binding proteins (eg. FMRP, G3BP1) for the formation of ribonucleoparticles / RNA granules. The gene localizes in neuronal RNA granules in dendrites. Previous studies have demonstrated a role in regulation of mRNA translation (acting as translational inhibitor with its overexpression leading to reduced protein synthesis). CAPRIN1 interacts with FMRP and CYFIP1, both also involved in regulation of mRNA translation.
One individual with microdeletion (~1.4 Mb spanning 8 genes with CAPRIN1 the only predicted to be haploinsufficient) as well as 11 additional subjects with nonsense/splicing variants were identified, following CMA, ES or GS. [The gene has a pHaplo of 0.98 and pLI of 0.97 (LOEUF 0.31)].
Variants were mostly de novo, although one individual had inherited a nonsense variant from his affected father while one further from her unaffected mother.
qRT-PCR showed reduced mRNA levels in patient fibroblasts and PBMCs while cycloheximide treatment in fibroblasts resulted in partial rescue in expression of mutant allele. Western blot in fibroblasts confirmed reduced protein levels.
cDNA analysis revealed that c.279+1G>T variant resulted in out-of-frame skipping of ex3, while c.879G>A (last base of ex8) resulted in out-of-frame skipping of ex8 and degradation by NMD, with cycloheximide restoring expression of mutant allele. [ NM_005898.5 ]
The authors generated a CAPRIN1+/- hiPSC line using CRISPR/Cas9 and hiPSCs were differentiated into cortical neurons. Htz immature neurons displayed altered neuronal structure, accompanied by reduced neurite length similar to previous observations in mice.
Increased neuronal degeneration was observed. Ca+2 signals (described in literature to trigger or contribute to neuronal death) were increased compared to controls. Increase in reactive oxygen species (ROS) following Ca+2 overload was also demonstrated, likely contributing to neuronal death.
Given the gene's role in regulation of mRNA translation, the authors assessed global de novo protein synthesis in neurons based on pyromicin incorporation (SUnSET assay) with findings supporting the impact of CAPRIN1 haploinsufficiency.
Heterozygous neurons were shown to display abnormal firing properties similar to a previously reported mouse model.
Mouse model : apart from the findings discussed above (abnormal neuronal structure and firing properties), heterozygous mice displayed similar features to the cohort described eg. reduced sociability and weaker preference for social novelty (as in ASD), difficulties in reversal learning (for ID), sporadic occurrence of seizures upon Morris water maze/contextual fearing tests and epileptic-like fEPSP after LTP. Breathing problems were noted in Carpin1-/- mice. Ear conditional ko was associated with early-onset progressive hearing loss and reduced protection from noise exposure which might be in line with few individuals with hearing impairment.Created: 3 Sep 2022, 10:24 a.m. | Last Modified: 3 Sep 2022, 10:24 a.m.
Panel Version: 0.4928
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Phenotypes
Global developmental delay; Delayed speech and language development; Intellectual disability; Autistic behavior; Seizures
Publications
Green List (high evidence)
12 individuals reported with ID and language impairment. Other features included seizures (4 individuals), hands and feet malformations (5 individuals), breathing problems (6 individuals), ocular problems (4 individuals) and hearing problems (3 individuals).
All of the variants were nonsense (NMD-predicted) or splicing variants. 10 were de novo, 1 was inherited from an affected father. Functional studies supported pathogenicity.
Sources: LiteratureCreated: 1 Sep 2022, 6:29 a.m.
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Phenotypes
Neurodevelopmental disorder, CAPRIN1-related MONDO:0700092
Publications
Variants in this GENE are reported as part of current diagnostic practice
Phenotypes for gene: CAPRIN1 were changed from Neurodevelopmental disorder, CAPRIN1-related MONDO:0700092; Neurodegeneration, childhood-onset, with cerebellar ataxia and cognitive decline, MIM# 620636 to Neurodevelopmental disorder with language impairment, autism, and attention deficit-hyperactivity disorder, MIM# 620782; Neurodegeneration, childhood-onset, with cerebellar ataxia and cognitive decline, MIM# 620636
Phenotypes for gene: CAPRIN1 were changed from Neurodevelopmental disorder, CAPRIN1-related MONDO:0700092; Neurodegeneration, childhood-onset, with cerebellar ataxia and cognitive decline, MIM# 620636 to Neurodevelopmental disorder, CAPRIN1-related MONDO:0700092; Neurodegeneration, childhood-onset, with cerebellar ataxia and cognitive decline, MIM# 620636
Phenotypes for gene: CAPRIN1 were changed from Neurodevelopmental disorder, CAPRIN1-related MONDO:0700092 to Neurodevelopmental disorder, CAPRIN1-related MONDO:0700092; Neurodegeneration, childhood-onset, with cerebellar ataxia and cognitive decline, MIM# 620636
Publications for gene: CAPRIN1 were set to 35979925; 35977029; 28135719; 31398340
Publications for gene: CAPRIN1 were set to 35979925
Gene: caprin1 has been classified as Green List (High Evidence).
Gene: caprin1 has been classified as Green List (High Evidence).
gene: CAPRIN1 was added gene: CAPRIN1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature Mode of inheritance for gene: CAPRIN1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: CAPRIN1 were set to 35979925 Phenotypes for gene: CAPRIN1 were set to Neurodevelopmental disorder, CAPRIN1-related MONDO:0700092 Review for gene: CAPRIN1 was set to GREEN gene: CAPRIN1 was marked as current diagnostic
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.