Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PP3
The ENST00000402686.8(POMT1):c.803G>A(p.Arg268His) variant causes a missense change. The variant allele was found at a frequency of 0.000039 in 1,614,038 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. R268R) has been classified as Likely benign.
POMT1 (HGNC:9202): (protein O-mannosyltransferase 1) The protein encoded by this gene is an O-mannosyltransferase that requires interaction with the product of the POMT2 gene for enzymatic function. The encoded protein is found in the membrane of the endoplasmic reticulum. Defects in this gene are a cause of Walker-Warburg syndrome (WWS) and limb-girdle muscular dystrophy type 2K (LGMD2K). Several transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Oct 2008]
Uncertain significance, criteria provided, single submitter
clinical testing
GeneDx
Aug 31, 2021
Not observed at significant frequency in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 22549409) -
Uncertain significance, criteria provided, single submitter
clinical testing
Revvity Omics, Revvity
Sep 27, 2023
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Uncertain significance, criteria provided, single submitter
clinical testing
Eurofins Ntd Llc (ga)
Jul 17, 2017
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not specified Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Genetic Services Laboratory, University of Chicago
Sep 02, 2016
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Neurodevelopmental abnormality Uncertain:1
Uncertain significance, no assertion criteria provided
clinical testing
Department of Genetics, Rouen University Hospital, Normandy Center for Genomic and Personalized Medicine
Apr 03, 2020
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Autosomal recessive limb-girdle muscular dystrophy type 2K Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Illumina Laboratory Services, Illumina
Jan 12, 2018
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
Inborn genetic diseases Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Ambry Genetics
Jul 13, 2021
The c.869G>A (p.R290H) alteration is located in exon 9 (coding exon 8) of the POMT1 gene. This alteration results from a G to A substitution at nucleotide position 869, causing the arginine (R) at amino acid position 290 to be replaced by a histidine (H). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -
Walker-Warburg congenital muscular dystrophy;C1836373:Autosomal recessive limb-girdle muscular dystrophy type 2K;C5436962:Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B1 Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Labcorp Genetics (formerly Invitae), Labcorp
Nov 01, 2022
This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 290 of the POMT1 protein (p.Arg290His). This variant is present in population databases (rs369644530, gnomAD 0.008%). This missense change has been observed in individual(s) with clinical features of POMT1-related conditions (Invitae). ClinVar contains an entry for this variant (Variation ID: 436376). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt POMT1 protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -