3-33068245-G-T

Position:

chr3-33068245-G-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PS1_ModeratePM1PM2PM5PP3_ModeratePP5_Very_Strong

The NM_000404.4(GLB1):c.442C>A(p.Arg148Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000818 in 1,613,974 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 nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin UniProt. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R148L) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000083 ( 0 hom. )

Consequence

GLB1
NM_000404.4 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8O:1

Conservation

PhyloP100: 2.81

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PS1

Transcript NM_000404.4 (GLB1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in UniProt

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 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 chr3-33068245-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 92907.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.923

PP5

Variant 3-33068245-G-T is Pathogenic according to our data. Variant chr3-33068245-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 551757.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr3-33068245-G-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GLB1	NM_000404.4 linkuse as main transcript	c.442C>A	p.Arg148Ser	missense_variant	4/16	ENST00000307363.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GLB1	ENST00000307363.10 linkuse as main transcript	c.442C>A	p.Arg148Ser	missense_variant	4/16	1	NM_000404.4	P2

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152130

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000162

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000361

AC:

AN:

249276

Hom.:

AF XY:

0.0000444

AC XY:

AN XY:

135250

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000796

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000828

AC:

121

AN:

1461726

Hom.:

Cov.:

AF XY:

0.0000770

AC XY:

AN XY:

727156

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000998

Gnomad4 OTH exome

AF:

0.000166

GnomAD4 genome

AF:

0.0000723

AC:

AN:

152248

Hom.:

Cov.:

AF XY:

0.0000537

AC XY:

AN XY:

74440

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000162

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000117

Hom.:

Bravo

AF:

0.0000529

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000367

AC:

ExAC

AF:

0.0000331

AC:

EpiCase

AF:

0.000218

EpiControl

AF:

0.000119

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jan 25, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jan 17, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Aug 02, 2021	Published functional studies demonstrate R148S leads to a decrease in enzymatic activity (Zhang et al., 2000); Not observed at significant frequency in large population cohorts (Lek et al., 2016); 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: 20175788, 10839995, 33240792, 16674934, 29352662, 15365997, 16763919, 25600812, 18353697, 22784478, 10841810, 24024947) -

Mucopolysaccharidosis, MPS-IV-B;C0268271:Infantile GM1 gangliosidosis;C0268272:GM1 gangliosidosis type 2;C0268273:GM1 gangliosidosis type 3

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Jul 30, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	May 15, 2017	- -

GLB1-related disorder

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Sep 03, 2023

The GLB1 c.442C>A variant is predicted to result in the amino acid substitution p.Arg148Ser. This variant has been reported in multiple individuals with GM1 gangliosidosis (see for example, Hinek et al. 2000. PubMed ID: 10841810; Table 1, Hofer et al. 2010. PubMed ID: 20175788; Table 1, Nestrasil et al. 2017. PubMed ID: 29352662). An in vitro experimental study suggests this variant impacts protein function (Table 2, Zhang et al. 2000. PubMed ID: 10839995). This variant is reported in 0.0086% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/3-33109737-G-T). Additionally, two different nucleotide changes that affect the same amino acid (p.Arg148Cys and p.Arg148His) have been classified as pathogenic and likely pathogenic, respectively (Internal Data, PreventionGenetics). The p.Arg148Ser variant is interpreted as pathogenic. -

Mucopolysaccharidosis, MPS-IV-B

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

May 11, 2018

Variant summary: GLB1 c.442C>A (p.Arg148Ser) results in a non-conservative amino acid change located in the Glycoside hydrolase 35 catalytic domain 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 4.3e-05 in 276992 control chromosomes (gnomAD and publications). This frequency is not significantly higher than expected for a pathogenic variant in GLB1 causing GM1 gangliosidosis (4.3e-05 vs 2.00e-03), allowing no conclusion about variant significance. The variant, c.442C>A, has been reported in the literature in several individuals affected with GM1 gangliosidosis (Zhang_2000, Hofer_2010, Nestrasil_2018). 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 maturation and enzyme activity, with both being significantly reduced in the presence of the variant (Zhang_2000). Additionally, other variants at the Arg148 residue have been reported as associated with disease (p.Arg148Cys and p.Arg148His), suggesting that this codon is important for function. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as pathogenic. -

GM1 gangliosidosis;C0086652:Mucopolysaccharidosis, MPS-IV-B

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 31, 2024

This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 148 of the GLB1 protein (p.Arg148Ser). This variant is present in population databases (rs192732174, gnomAD 0.009%). This missense change has been observed in individual(s) with GM1 gangliosidosis (PMID: 10839995, 20175788, 25600812). ClinVar contains an entry for this variant (Variation ID: 551757). 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: 10839995). This variant disrupts the p.Arg148 amino acid residue in GLB1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 15986423, 17221873, 23151865, 25936995). 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

Other:1

not provided, no classification provided

phenotyping only

GenomeConnect - GM1

Variant interpreted as Pathogenic and reported on 09-25-2014 by Lab or GTR ID 239772. GenomeConnect-GM1 assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. Registry team members make no attempt to reinterpret the clinical significance of the variant. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.41

BayesDel_noAF

Pathogenic

0.55

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.88

.;.;D

Eigen

Pathogenic

0.81

Eigen_PC

Pathogenic

0.68

FATHMM_MKL

Uncertain

0.96

LIST_S2

Pathogenic

0.97

.;.;D

M_CAP

Pathogenic

0.79

MetaRNN

Pathogenic

0.92

D;D;D

MetaSVM

Pathogenic

0.99

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Uncertain

0.59

PROVEAN

Pathogenic

-4.7

D;D;D

REVEL

Pathogenic

0.95

Sift

Uncertain

0.020

D;D;D

Sift4G

Uncertain

0.044

D;D;D

Vest4

0.95

MVP

0.98

MPC

0.92

ClinPred

0.99

GERP RS

5.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

gMVP

0.99

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

Details are displayed if max score is > 0.2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over