Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1PM2
The NM_017739.4(POMGNT1):āc.1456C>Gā(p.Arg486Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000192 in 1,614,176 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (ā ā ). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R486L) has been classified as Uncertain significance.
POMGNT1 (HGNC:19139): (protein O-linked mannose N-acetylglucosaminyltransferase 1 (beta 1,2-)) This gene encodes a type II transmembrane protein that resides in the Golgi apparatus. It participates in O-mannosyl glycosylation and is specific for alpha linked terminal mannose. Mutations in this gene may be associated with muscle-eye-brain disease and several congenital muscular dystrophies. Alternatively spliced transcript variants that encode different protein isoforms have been described. [provided by RefSeq, Feb 2014]
TSPAN1 (HGNC:20657): (tetraspanin 1) The protein encoded by this gene is a member of the transmembrane 4 superfamily, also known as the tetraspanin family. Most of these members are cell-surface proteins that are characterized by the presence of four hydrophobic domains. The proteins mediate signal transduction events that play a role in the regulation of cell development, activation, growth and motility. [provided by RefSeq, Jul 2008]
Verdict is Uncertain_significance. Variant got 4 ACMG points.
PM1
In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_017739.4
PM2
Very rare variant in population databases, with high coverage;
Uncertain significance, criteria provided, single submitter
clinical testing
Eurofins Ntd Llc (ga)
Sep 20, 2016
- -
Uncertain significance, criteria provided, single submitter
clinical testing
Revvity Omics, Revvity
Sep 27, 2023
- -
not specified Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Genetic Services Laboratory, University of Chicago
Aug 30, 2016
- -
Inborn genetic diseases Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Ambry Genetics
Jul 24, 2022
The c.1456C>G (p.R486G) alteration is located in exon 17 (coding exon 16) of the POMGNT1 gene. This alteration results from a C to G substitution at nucleotide position 1456, causing the arginine (R) at amino acid position 486 to be replaced by a glycine (G). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -
Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B3;C3150417:Autosomal recessive limb-girdle muscular dystrophy type 2O;C3151519:Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A3;C4310704:Retinitis pigmentosa 76 Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Fulgent Genetics, Fulgent Genetics
Dec 16, 2021
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Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B3;C3150417:Autosomal recessive limb-girdle muscular dystrophy type 2O Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Labcorp Genetics (formerly Invitae), Labcorp
Oct 04, 2022
This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 486 of the POMGNT1 protein (p.Arg486Gly). This variant is present in population databases (rs534543454, gnomAD 0.002%). This variant has not been reported in the literature in individuals affected with POMGNT1-related conditions. ClinVar contains an entry for this variant (Variation ID: 291060). 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 POMGNT1 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. -
Muscle eye brain disease Uncertain:1
Uncertain significance, no assertion criteria provided