rs371546950

Positions:

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1PM2PM5PP3_StrongPP5

The NM_000404.4(GLB1):c.809A>G(p.Tyr270Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,614,088 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. Y270H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000062 ( 0 hom. )

Consequence

GLB1
NM_000404.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:1

Conservation

PhyloP100: 7.66

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 11 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 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 chr3-33051989-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 284172.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.956

PP5

Variant 3-33051988-T-C is Pathogenic according to our data. Variant chr3-33051988-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 198726.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Likely_pathogenic=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GLB1	NM_000404.4 linkuse as main transcript	c.809A>G	p.Tyr270Cys	missense_variant	8/16	ENST00000307363.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GLB1	ENST00000307363.10 linkuse as main transcript	c.809A>G	p.Tyr270Cys	missense_variant	8/16	1	NM_000404.4	P2

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152212

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000160

AC:

AN:

249476

Hom.:

AF XY:

0.0000222

AC XY:

AN XY:

135350

show subpopulations

Gnomad AFR exome

AF:

0.000129

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000883

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000616

AC:

AN:

1461876

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727240

show subpopulations

Gnomad4 AFR exome

AF:

0.0000896

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000360

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152212

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74362

show subpopulations

Gnomad4 AFR

AF:

0.0000241

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:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ESP6500AA

AF:

0.000261

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000331

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Apr 12, 2017

- -

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

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Oct 26, 2023

This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 270 of the GLB1 protein (p.Tyr270Cys). This variant is present in population databases (rs371546950, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with GLB1-related conditions. ClinVar contains an entry for this variant (Variation ID: 198726). 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%. This variant disrupts the p.Tyr270 amino acid residue in GLB1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11511921, 19472408, 21520340). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Feb 18, 2023

Variant summary: GLB1 c.809A>G (p.Tyr270Cys) results in a non-conservative amino acid change located in the Glycoside hydrolase 35, catalytic domain (IPR031330) of the encoded protein sequence. Four of four in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.6e-05 in 249476 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.809A>G in individuals affected with Mucopolysaccharidosis Type IVB (Morquio Syndrome B) and no experimental evidence demonstrating its impact on protein function have been reported. Two ClinVar submitters have assessed the variant since 2014: both classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.73

BayesDel_addAF

Pathogenic

0.41

BayesDel_noAF

Pathogenic

0.59

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.86

.;.;.;D

Eigen

Pathogenic

0.95

Eigen_PC

Pathogenic

0.86

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.97

.;.;D;D

M_CAP

Pathogenic

0.69

MetaRNN

Pathogenic

0.96

D;D;D;D

MetaSVM

Pathogenic

1.1

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Uncertain

0.77

PROVEAN

Pathogenic

-8.4

D;D;D;D

REVEL

Pathogenic

0.96

Sift

Pathogenic

0.0

D;D;D;D

Sift4G

Pathogenic

0.0

D;D;D;D

Polyphen

1.0

.;.;D;.

Vest4

0.95

MVP

0.99

MPC

0.98

ClinPred

1.0

GERP RS

5.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

gMVP

0.95

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

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