rs72555358
Variant summary
Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1PM2PM5PP2PP3_StrongPP5
The NM_000404.4(GLB1):c.145C>T(p.Arg49Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000929 in 1,614,014 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R49P) 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 12 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| GLB1 | NM_000404.4 | c.145C>T | p.Arg49Cys | missense_variant | Exon 2 of 16 | ENST00000307363.10 | NP_000395.3 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| GLB1 | ENST00000307363.10 | c.145C>T | p.Arg49Cys | missense_variant | Exon 2 of 16 | 1 | NM_000404.4 | ENSP00000306920.4 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152156Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000120 AC: 3AN: 249536 AF XY: 0.00000739 show subpopulations
GnomAD4 exome AF: 0.00000958 AC: 14AN: 1461858Hom.: 0 Cov.: 31 AF XY: 0.00000825 AC XY: 6AN XY: 727226 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152156Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74316 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Infantile GM1 gangliosidosis Pathogenic:2
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A Homozygous missense variation in exon 2 of the GLB1 gene that results in the amino acid substitution of Cysteine for Arginine at codon 49 was detected. The observed variant c.145C>T (p.Arg49Cys) has not been reported in the 1000 genomes and has MAF of 0.001% in gnomAD databases. The in silico prediction of the variant is disease causing by PolyPhen-2 (HumDiv), SIFT and MutationTaster2. The reference codon is conserved across species. In summary, the variant meets our criteria to be classified as likely pathogenic. -
Mucopolysaccharidosis, MPS-IV-B Pathogenic:1
Variant summary: GLB1 c.145C>T (p.Arg49Cys) results in a non-conservative amino acid change located in the Glycoside hydrolase 35, catalytic domain (IPR031330) of 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 1.2e-05 in 249536 control chromosomes. c.145C>T has been reported in the literature in individuals affected with Mucopolysaccharidosis Type IVB (Morquio Syndrome B) and short stature (example, Huang_2018, Bidchol_2015, Georgiou_2004). These data indicate that the variant is likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in <10% of normal Beta-D galactosidase activity in a homozygous individual (example Bidchol_2015). Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
GM1 gangliosidosis;C0086652:Mucopolysaccharidosis, MPS-IV-B Pathogenic:1
For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg49 amino acid residue in GLB1. Other variant(s) that disrupt this residue have been observed in individuals with GLB1-related conditions (PMID: 15986423, 30267299), which suggests that this may be a clinically significant amino acid residue. 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. ClinVar contains an entry for this variant (Variation ID: 923). This missense change has been observed in individual(s) with GM1-gangliosidosis (PMID: 15365997, 21520340, 25936995, 26646981; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is present in population databases (rs72555358, gnomAD 0.01%). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 49 of the GLB1 protein (p.Arg49Cys). -
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. -
not provided Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at