NM_000404.4:c.175C>T
Variant summary
Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Very_Strong
The NM_000404.4(GLB1):c.175C>T(p.Arg59Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000223 in 1,613,976 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R59H) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000404.4 missense
Scores
Clinical Significance
Conservation
Publications
- GM1 gangliosidosisInheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health, ClinGen
- GM1 gangliosidosis type 3Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp
- mucopolysaccharidosis type 4BInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, ClinGen, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
- GM1 gangliosidosis type 1Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet
- GM1 gangliosidosis type 2Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp
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ACMG classification
Our verdict: Pathogenic. The variant received 19 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000197 AC: 3AN: 152164Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000481 AC: 12AN: 249480 AF XY: 0.0000517 show subpopulations
GnomAD4 exome AF: 0.0000226 AC: 33AN: 1461812Hom.: 0 Cov.: 31 AF XY: 0.0000179 AC XY: 13AN XY: 727206 show subpopulations
GnomAD4 genome AF: 0.0000197 AC: 3AN: 152164Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3AN XY: 74320 show subpopulations
ClinVar
Submissions by phenotype
not provided Pathogenic:3
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Mucopolysaccharidosis, MPS-IV-B;C0268271:Infantile GM1 gangliosidosis;C0268272:GM1 gangliosidosis type 2;C0268273:GM1 gangliosidosis type 3 Pathogenic:1
This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
GM1 gangliosidosis;C0086652:Mucopolysaccharidosis, MPS-IV-B Pathogenic:1
This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 59 of the GLB1 protein (p.Arg59Cys). This variant is present in population databases (rs756878418, gnomAD 0.04%). This missense change has been observed in individual(s) with GM1 gangliosidosis (PMID: 15714521, 16941474, 17309651). ClinVar contains an entry for this variant (Variation ID: 496895). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt GLB1 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects GLB1 function (PMID: 15714521). This variant disrupts the p.Arg59 amino acid residue in GLB1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10338095, 16941474, 17309651, 17664528). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -
GM1 gangliosidosis Pathogenic:1
Variant summary: GLB1 c.175C>T (p.Arg59Cys) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4.8e-05 in 249480 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in GLB1 causing GM1 Gangliosidosis (4.8e-05 vs 0.00091), allowing no conclusion about variant significance. c.175C>T has been reported in the literature in individuals affected with GM1 Gangliosidosis (e.g. Caciotti_2005, Santamaria_2006, 2007). These data indicate that the variant is likely to be associated with disease. A different variant affecting the same codon has been classified as pathogenic by our lab (c.176G>A, p.Arg59His), supporting the critical relevance of codon 59 to GLB1 protein function. At least one publication reports experimental evidence evaluating an impact on protein function, finding that the variant rendered GLB1 enzymatically inactive (Caciotti_2005). The following publications have been ascertained in the context of this evaluation (PMID: 15714521, 16941474, 17309651). ClinVar contains an entry for this variant (Variation ID: 496895). Based on the evidence outlined above, the variant was classified as pathogenic. -
Infantile GM1 gangliosidosis Pathogenic:1
ACMG classification criteria: PS4 moderate, PM2 moderate, PM3 strong, PP3 supporting, PP4 supporting -
GM1 gangliosidosis type 2 Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at