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| Intellectual disability - microarray and sequencing v3.1518 | NRCAM |
Konstantinos Varvagiannis gene: NRCAM was added gene: NRCAM was added to Intellectual disability. Sources: Literature Mode of inheritance for gene: NRCAM was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: NRCAM were set to 35108495 Phenotypes for gene: NRCAM were set to Hypotonia; Hypertonia; Spasticity; Global developmental delay; Intellectual disability; Microcephaly; Behavioral abnormality; Neuropathy; Hearing abnormality; Abnormality of the eye; Abnormality of the skeletal system; Scoliosis; Abnormality of the face Penetrance for gene: NRCAM were set to Complete Review for gene: NRCAM was set to GREEN Added comment: Kurolap et al (2022 - PMID: 35108495) describe the phenotype of 10 individuals (from 8 families) with biallelic variants in NRCAM. Features included tone abnormalities (hypotonia in 4/10, hypertonia/spasticity in 4/10), DD (8/10 - 7 families) and cognitive impairment (in 7/10 - 6 fam), neuropathy (4/10 - incl. 2 sibs without DD/ID). Other phenotypes incl. FTT (2/8), microcephaly (3/6), variable behavioral issues (3/5), abnormalities from the eyes/vision (6/8 - cataract in 2), abnormal hearing (3/7) or skeletal findings (8/9 - incl. scoliosis in 5). Nonspecific facial features were reported in 5/8. Previous metabolic, genetic (incl. karyotype or CMA, FMR1, testing for Steinert disease or SMA) or other work-up (e.g. muscle biopsy) is reported for several subjects but was normal/non-diagnostic. All were investigated by WES/WGS which revealed biallelic NRCAM variants. Sanger sequencing was used for confirmation and segregation analyses, with compatible results in several affected/unaffected sibs tested. There were no alternative explanations for the NDD phenotype with the exception of one subject with a mosaic functionally characterized LP KRAS variant suspected to contribute to his phenotype. NRCAM encodes neuronal cell adhesion molecule (CAM). CAMs are membrane bound proteins with important role in tissue morphogenesis and maintenance. They mediate interactions between neighboring cells or cells and the extracellular matrix. The L1 subgroup of immunoglobulin CAMS - consisting of L1CAM, neurofascin, NRCAM, CHL1 - is the most abundant in the CNS with several critical functions in CNS development, among others in neural cell differentiation, axonal growth and guidance, myelination, synapse formation. Pathogenic L1CAM (XL) and NFASC variants (AR) are associated with NDD. Different missense (N=7), stopgain/frameshift (N=3), a splice variant (NM_001037132.2:c.2647-2A>G) as well as a deep intronic one (c.230+824G>C / rs575851831). Variants occurred in different domains with a cluster (42%) in the fibronectin III domain. Missense SNVs were ultrarare or not present in gnomAD, occurred in conserved residues, with several in silico predictions in favor of a deleterious effect. Structural modelling suggested that all substitutions occurred at residues exposed to solvent and possible abrogated interaction with other proteins. There were no expression studies performed at the mRNA/protein level. The splice variant is predicted to cause ex22 skipping leading to frameshift. The deep intronic variant is predicted to disrupt a site for spl. regulator SC35 and may cause activation of a cryptic acceptor site with inclusion of a cryptic exon. The zebrafish nrcama gene is the sole ortholog of human NRCAM, with another gene proposed as possible ortholog (nrcamb) mapping upon BLAST analysis to cntn1a. The authors performed CRISPR-Cas9 mutagenesis in zebrafish introducing a partial deletion of ex18 and 19. Mutant zebrafish were viable, displayed altered axonal projections and abnormal swimming behavior (increased movement in darkness). Currently, there is no NRCAM-associated phenotype in OMIM/G2P/SysID. PanelApp Australia includes NRCAM in its ID panel with green rating. Consider inclusion probably with green (>3 individuals/families/variants, segregation, gene in the L1-Ig CAM family causing NDD, zebrafish model) or amber rating (ID not a universal feature, variant effect not studied). Sources: Literature |
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| Intellectual disability - microarray and sequencing v3.1242 | L1CAM | Arina Puzriakova Phenotypes for gene: L1CAM were changed from Hydrocephalus due to aqueductal stenosis, 307000MASA syndrome, 303350CRASH syndrome, 303350Hydrocephalus with Hirschsprung disease, 307000Hydrocephalus with congenital idiopathic intestinal pseudoobstruction, 307000Corpus callosum, partial agenesis of, 304100; MENTAL RETARDATION-APHASIA-SHUFFLING GAIT-ADDUCTED THUMBS SYNDROME (MASA) to Corpus callosum, partial agenesis of, OMIM:304100; CRASH syndrome, OMIM:303350; MASA syndrome, OMIM:303350; Hydrocephalus due to aqueductal stenosis, OMIM:307000; Hydrocephalus with congential idiopathic intestinal pseudoobstruction, OMIM:307000; Hydrocephalus with Hirschsprung disease, OMIM:307000 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Intellectual disability - microarray and sequencing v2.468 | L1CAM | Louise Daugherty Source Victorian Clinical Genetics Services was added to L1CAM. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Intellectual disability - microarray and sequencing | L1CAM | BRIDGE consortium edited their review of L1CAM | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Intellectual disability - microarray and sequencing | L1CAM | BRIDGE consortium edited their review of L1CAM | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Intellectual disability - microarray and sequencing | L1CAM | BRIDGE consortium reviewed L1CAM | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||