rs111840209

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1PM2PM5PP2PP3_Moderate

The NM_000404.4(GLB1):​c.623G>T​(p.Arg208Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,860 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R208H) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

GLB1
NM_000404.4 missense

Scores

4
5
9

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -0.479

Publications

10 publications found
Variant links:
Genes affected
GLB1 (HGNC:4298): (galactosidase beta 1) This gene encodes a member of the glycosyl hydrolase 35 family of proteins. Alternative splicing results in multiple transcript variants, at least one of which encodes a preproprotein that is proteolytically processed to generate the mature lysosomal enzyme. This enzyme catalyzes the hydrolysis of a terminal beta-linked galactose residue from ganglioside substrates and other glycoconjugates. Mutations in this gene may result in GM1-gangliosidosis and Morquio B syndrome. [provided by RefSeq, Nov 2015]
GLB1 Gene-Disease associations (from GenCC):
  • GM1 gangliosidosis
    Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health, ClinGen
  • GM1 gangliosidosis type 3
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp
  • mucopolysaccharidosis type 4B
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, ClinGen, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
  • GM1 gangliosidosis type 1
    Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet
  • GM1 gangliosidosis type 2
    Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 9 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_000404.4
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr3-33058200-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 939.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
PP2
Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 110 curated pathogenic missense variants (we use a threshold of 10). The gene has 24 curated benign missense variants. Gene score misZ: 0.79419 (below the threshold of 3.09). Trascript score misZ: 1.1264 (below the threshold of 3.09). GenCC associations: The gene is linked to mucopolysaccharidosis type 4B, GM1 gangliosidosis, GM1 gangliosidosis type 2, GM1 gangliosidosis type 3, GM1 gangliosidosis type 1.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.905

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
GLB1NM_000404.4 linkc.623G>T p.Arg208Leu missense_variant Exon 6 of 16 ENST00000307363.10 NP_000395.3

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
GLB1ENST00000307363.10 linkc.623G>T p.Arg208Leu missense_variant Exon 6 of 16 1 NM_000404.4 ENSP00000306920.4

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
AF:
6.84e-7
AC:
1
AN:
1461860
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
727228
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33478
American (AMR)
AF:
0.00
AC:
0
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39698
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53414
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
8.99e-7
AC:
1
AN:
1111996
Other (OTH)
AF:
0.00
AC:
0
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
32
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.00000378

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

GM1 gangliosidosis;C0086652:Mucopolysaccharidosis, MPS-IV-B Uncertain:1
Jun 29, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 208 of the GLB1 protein (p.Arg208Leu). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with GLB1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C15"). This variant disrupts the p.Arg208 amino acid residue in GLB1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 8213816, 10338095, 15714521, 17309651, 23337983). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.12
BayesDel_addAF
Uncertain
0.15
D
BayesDel_noAF
Uncertain
-0.030
CADD
Benign
3.3
DANN
Benign
0.96
DEOGEN2
Uncertain
0.67
.;.;D;D
Eigen
Benign
-1.1
Eigen_PC
Benign
-1.4
FATHMM_MKL
Benign
0.41
N
LIST_S2
Benign
0.85
.;.;T;T
M_CAP
Pathogenic
0.61
D
MetaRNN
Pathogenic
0.91
D;D;D;D
MetaSVM
Pathogenic
1.0
D
PhyloP100
-0.48
PrimateAI
Benign
0.25
T
PROVEAN
Pathogenic
-5.7
D;D;D;D
REVEL
Uncertain
0.49
Sift
Uncertain
0.0070
D;D;T;D
Sift4G
Benign
0.067
T;T;T;T
Vest4
0.59
MutPred
0.80
Loss of methylation at R208 (P = 0.0277);.;.;.;
MVP
0.75
MPC
0.63
ClinPred
0.99
D
GERP RS
-8.3
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
gMVP
0.85
Mutation Taster
=53/47
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.0
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs111840209; hg19: chr3-33099691; API