Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong
The NM_017739.4(POMGNT1):c.1814G>C(p.Arg605Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000479 in 1,460,604 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R605C) has been classified as Likely pathogenic.
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 Pathogenic. Variant got 18 ACMG points.
PM1
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_017739.4
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr1-46189539-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 56589.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.988
PP5
Variant 1-46189539-C-G is Pathogenic according to our data. Variant chr1-46189539-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3998.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-46189539-C-G is described in Lovd as [Likely_pathogenic]. Variant chr1-46189539-C-G is described in Lovd as [Pathogenic]. Variant chr1-46189539-C-G is described in Lovd as [Pathogenic].
Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B3 Pathogenic:3
Pathogenic, no assertion criteria provided
literature only
OMIM
May 26, 2009
- -
Pathogenic, criteria provided, single submitter
clinical testing
Institute of Human Genetics, University of Leipzig Medical Center
Sep 08, 2022
This variant was identified as homozygous._x000D_ Criteria applied: PM5_STR, PM1, PM3, PM2_SUP, PP3 -
Likely pathogenic, criteria provided, single submitter
clinical testing
3billion
Jan 03, 2022
The variant observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.000008, PM2_M). In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.903, PP3_P). The varianthas been previously reported multiple times as pathogenic or likely pathogenic (ClinVar: VCV000003998). Therefore, this variant is classified as likely pathogenic according to the recommendation of ACMG/AMP guideline. -
Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A3 Pathogenic:2
Pathogenic, criteria provided, single submitter
clinical testing
Baylor Genetics
Dec 01, 2021
- -
Pathogenic, criteria provided, single submitter
clinical testing
Institute of Human Genetics, University of Leipzig Medical Center
Jun 28, 2023
Criteria applied: PM5_STR,PM1,PM3,PM2_SUP,PP3 -
Muscle eye brain disease Pathogenic:2
Likely pathogenic, criteria provided, single submitter
Likely pathogenic, criteria provided, single submitter
curation
Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard
Jan 24, 2023
The p.Arg605Pro variant in POMGNT1 has been reported in three individuals with muscular dystrophy-dystroglycanopathy (PMID: 19299310, 19679478), and has been identified in 0.01% (1/9970) of Ashkenazi Jewish chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs267606962). Although this variant has been seen in the general population in a heterozygous state, its frequency is low enough to be consistent with a recessive carrier frequency. This variant has also been reported in ClinVar (Variation ID#:3998) and has been interpreted as pathogenic by multiple labs. Of the three affected individuals, two were homozygotes, which increases the likelihood that the p.Arg605Pro variant is pathogenic (PMID: 19299310, 19679478). Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. One additional likely pathogenic variant, resulting in a different amino acid change at the same position, p.Arg605His, has been reported in association with disease in the literature, slightly supporting that a change at this position may not be tolerated (PMID: 33726816, 17154333/Variation ID: 56589). In summary, although additional studies are required to fully establish its clinical significance, this variant is likely pathogenic for autosomal recessive muscular dystrophy-dystroglycanopathy. ACMG/AMP Criteria applied: PM3, PM5_Supporting, PP3, PM2 (Richards 2015). -
Muscular dystrophy-dystroglycanopathy (congenital with intellectual disability), type B3;C3150417:Autosomal recessive limb-girdle muscular dystrophy type 2O Pathogenic:1
Pathogenic, criteria provided, single submitter
clinical testing
Labcorp Genetics (formerly Invitae), Labcorp
Oct 23, 2022
For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg605 amino acid residue in POMGNT1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 21361872, 24731844). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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 expected to disrupt POMGNT1 protein function. ClinVar contains an entry for this variant (Variation ID: 3998). This missense change has been observed in individuals with muscular dystrophy-dystroglycanopathy (PMID: 19299310, 19679478, 23689641, 24731844). This variant is present in population databases (rs267606962, gnomAD 0.01%). This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 605 of the POMGNT1 protein (p.Arg605Pro). -
not provided Pathogenic:1
Pathogenic, criteria provided, single submitter
clinical testing
Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen