rs72555370
Variant summary
Our verdict is Pathogenic. The variant received 15 ACMG points: 15P and 0B. PM2PM5PP2PP3_ModeratePP5_Very_Strong
The NM_000404.4(GLB1):c.202C>T(p.Arg68Trp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000248 in 1,613,844 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. R68L) 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 15 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152180Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000281 AC: 7AN: 249454 AF XY: 0.0000369 show subpopulations
GnomAD4 exome AF: 0.0000246 AC: 36AN: 1461664Hom.: 0 Cov.: 31 AF XY: 0.0000220 AC XY: 16AN XY: 727128 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152180Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3AN XY: 74344 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
GM1 gangliosidosis type 3 Pathogenic:1
The missense variant, c.202C>T in exon 2 of GLB1 was observed in heterozygous state in the proband and mother (Caciotti et al.,2003; VCV000000944.10). This variant is present in 40 individuals in heterozygous state and absent in homozygous state in gnomAD (v4.1.0). This variant is present in four individuals in heterozygous state and absent in homozygous state in our in-house database of 3673 exomes. The clinical findings observed in the proband are in concordance with. Symptoms of GM1-gangliosidosis, type III can begin in late childhood with unsteady gait, speech disturbance and spine abnormalities. -
not provided Pathogenic:1
Published functional studies found this variant is associated with significantly reduced enzyme activity (PMID: 12644936); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 33737400, 31367523, 21497194, 12644936, 29352662, 25936995, 31761138) -
Mucopolysaccharidosis, MPS-IV-B;C0268271:Infantile GM1 gangliosidosis;C0268272:GM1 gangliosidosis type 2;C0268273:GM1 gangliosidosis type 3 Pathogenic:1
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GM1 gangliosidosis;C0086652:Mucopolysaccharidosis, MPS-IV-B Pathogenic:1
This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 68 of the GLB1 protein (p.Arg68Trp). This variant is present in population databases (rs72555370, gnomAD 0.01%). This missense change has been observed in individual(s) with GM1 gangliosidosis (PMID: 12644936, 25936995). ClinVar contains an entry for this variant (Variation ID: 944). 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 GLB1 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects GLB1 function (PMID: 12644936). This variant disrupts the p.Arg68 amino acid residue in GLB1. Other variant(s) that disrupt this residue have been observed in individuals with GLB1-related conditions (PMID: 19472408, 29439846), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic. -
Infantile GM1 gangliosidosis Pathogenic:1
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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