rs398123351
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.1769G>A(p.Arg590His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000266 in 1,613,732 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. R590C) has been classified as 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
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| GLB1 | NM_000404.4 | c.1769G>A | p.Arg590His | missense_variant | Exon 16 of 16 | ENST00000307363.10 | NP_000395.3 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| GLB1 | ENST00000307363.10 | c.1769G>A | p.Arg590His | missense_variant | Exon 16 of 16 | 1 | NM_000404.4 | ENSP00000306920.4 | ||
| GLB1 | ENST00000307377.12 | c.1376G>A | p.Arg459His | missense_variant | Exon 13 of 13 | 1 | ENSP00000305920.8 | |||
| GLB1 | ENST00000399402.7 | c.1679G>A | p.Arg560His | missense_variant | Exon 16 of 16 | 2 | ENSP00000382333.2 |
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152160Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000120 AC: 3AN: 249130 AF XY: 0.0000222 show subpopulations
GnomAD4 exome AF: 0.0000267 AC: 39AN: 1461572Hom.: 0 Cov.: 31 AF XY: 0.0000303 AC XY: 22AN XY: 727092 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152160Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74318 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Pathogenic:1
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Progressive familial intrahepatic cholestasis Pathogenic:1
Variant summary: ABCB4 c.1769G>A (p.Arg590Gln) results in a conservative amino acid change located in the ABC transporter-like, ATP-binding domain (IPR003439) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.0045 in 251094 control chromosomes in the gnomAD database, including 4 homozygotes. The observed variant frequency is approximately 2.0 fold of the estimated maximal expected allele frequency for a pathogenic variant in ABCB4 causing Familial Intrahepatic Cholestasis phenotype (0.0022), strongly suggesting that the variant is benign. c.1769G>A has been reported in the literature among individuals with ABCB4-related conditions such as Anicteric Cholestasis, low phospholipid-associated cholelithiasis (LPAC), Progressive familial intrahepatic cholestasis (example, Ziol_2008, Tuan Huynh_2019, Colombo_2011, Droge_2017). These data do not allow any conclusion about variant significance. At-least one co-occurrence in cis with another presumably pathogenic variant(s) has been reported (Colombo_2011, ABCB4 c.2284G>T, p.G762X), providing supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Seven clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with conflicting assessments (Benign/Likely Benign, n=2; VUS, n=5). Based on the evidence outlined above, the variant was classified as VUS-possibly benign. -
Infantile GM1 gangliosidosis;C0268272:GM1 gangliosidosis type 2;C0268273:GM1 gangliosidosis type 3 Pathogenic:1
NM_000404.2(GLB1):c.1769G>A(R590H) is a missense variant classified as likely pathogenic in the context of GLB1-related disorders. R590H has been observed in cases with relevant disease (PMID: 8213816, 27619815, Shekar_2019_(no PMID; poster), 26646981, 33737400). Functional assessments of this variant are available in the literature (PMID: 8213816, 21520340, 23337983). R590H has been observed in population frequency databases (gnomAD: SAS 0.003%). In summary, NM_000404.2(GLB1):c.1769G>A(R590H) is a missense variant that has been observed more frequently in cases with the relevant disease than in healthy populations. Please note: this variant was assessed in the context of healthy population screening. -
GM1 gangliosidosis Pathogenic:1
Variant summary: GLB1 c.1769G>A (p.Arg590His) results in a non-conservative amino acid change located in the galactose-binding domain (IPR048913) 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 249130 control chromosomes (gnomAD). c.1769G>A has been reported in the literature in individuals affected with GM1 Gangliosidosis (e.g. Boustany_1993, Regier_2016, Quaio_2020). Publications also reported experimental evidence evaluating an impact on protein function, and demonstrated decreased enzyme activity (e.g. Boustany_1993, Higaki_2011, Takai_2013). ClinVar contains an entry for this variant (Variation ID: 92901). Based on the evidence outlined above, the variant was classified as pathogenic. -
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 histidine, which is basic and polar, at codon 590 of the GLB1 protein (p.Arg590His). This variant is present in population databases (rs398123351, gnomAD 0.003%). This missense change has been observed in individuals with GM1-gangliosidosis (PMID: 8213816, 26646981). ClinVar contains an entry for this variant (Variation ID: 92901). 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: 8213816, 23337983). This variant disrupts the p.Arg590 amino acid residue in GLB1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 16941474, 17309651, 23430803). 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. -
Infantile GM1 gangliosidosis Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at