Genetic Variant NM_000404.4:c.602G>A (chr3-33058220-C-T) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PS3PM2PM5PP2PP3PP5_Very_Strong

The NM_000404.4(GLB1):c.602G>A(p.Arg201His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000372 in 1,614,018 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 (★★). ClinVar reports functional evidence for this variant: "SCV000321731: Functional studies found that this variant is associated with significantly reduced enzyme activity (Santamaria et al. 2007" and additional evidence is available in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R201C) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000059 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000035 ( 0 hom. )

Consequence

GLB1
NM_000404.4 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:15O:1

Conservation

PhyloP100: 7.50

Publications

47 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: ClinGen, Myriad Women’s Health
GM1 gangliosidosis type 3
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet
mucopolysaccharidosis type 4B
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), Orphanet, 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: Genomics England PanelApp, Orphanet

GLB1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PS3

PS3 evidence extracted from ClinVar submissions: SCV000321731: Functional studies found that this variant is associated with significantly reduced enzyme activity (Santamaria et al. 2007; Hofer et al., 2009); SCV001500297: PS3:Supporting; SCV000443184: Functional studies in individual leukocytes and fibroblasts carrying the p.Arg201His variant demonstrated a significant reduction in enzyme activity to between 2% and 2.5% of wildtype (Kaye et al. 1997; Caciotti et al. 2005).; SCV000966893: In vitro functional studies provide some evidence that the p. Arg201His variant may impact protein function (Kaye 1997, Iwasaki 2006, Santamaria 2007).; SCV000958646: Experimental studies have shown that this missense change affects GLB1 function (PMID: 9203065, 11504597, 16617000, 17664528).; SCV006071264: At least one publication reports experimental evidence evaluating an impact on protein function (Iwasaki_2006, Santamaria_2006). The most pronounced variant effect results in 2.4% of normal activity in fibroblasts from the patient carrying the homozygous variant (Santamaria_2006). PMID: 16617000, 16941474

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr3-33058221-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 925.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 3, GM1 gangliosidosis type 2, GM1 gangliosidosis type 1.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.803

PP5

Variant 3-33058220-C-T is Pathogenic according to our data. Variant chr3-33058220-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 198077.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000404.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
GLB1	NM_000404.4	MANE Select	c.602G>A	p.Arg201His	missense	Exon 6 of 16	NP_000395.3
GLB1	NM_001317040.2		c.746G>A	p.Arg249His	missense	Exon 7 of 17	NP_001303969.2
GLB1	NM_001079811.3		c.512G>A	p.Arg171His	missense	Exon 6 of 16	NP_001073279.2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
GLB1	ENST00000307363.10	TSL:1 MANE Select	c.602G>A	p.Arg201His	missense	Exon 6 of 16	ENSP00000306920.4	P16278
GLB1	ENST00000307377.12	TSL:1	c.341-4671G>A		intron	N/A	ENSP00000305920.8	E7EQ29
GLB1	ENST00000399402.7	TSL:2	c.512G>A	p.Arg171His	missense	Exon 6 of 16	ENSP00000382333.2	P16278

Frequencies

GnomAD3 genomes

AF:

0.0000592

AC:

AN:

152044

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:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.000103

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000643

AC:

AN:

249022

AF XY:

0.0000666

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000580

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000111

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000798

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000349

AC:

AN:

1461856

Hom.:

Cov.:

AF XY:

0.0000399

AC XY:

AN XY:

727226

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000671

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000504

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000812

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53406

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000333

AC:

AN:

1111996

Other (OTH)

AF:

0.0000166

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000591

AC:

AN:

152162

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74384

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41524

American (AMR)

AF:

0.00

AC:

AN:

15280

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.000193

AC:

AN:

5172

South Asian (SAS)

AF:

0.00

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10584

Middle Eastern (MID)

AF:

0.00340

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000103

AC:

AN:

68002

Other (OTH)

AF:

0.00

AC:

AN:

2108

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.503

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000852

Hom.:

Bravo

AF:

0.0000529

ExAC

AF:

0.0000911

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.000356

ClinVar

ClinVar submissions

Significance:Pathogenic/Likely pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (5)

Infantile GM1 gangliosidosis (3)

GM1 gangliosidosis (3)

GM1 gangliosidosis type 2 (2)

GM1 gangliosidosis;C0086652:Mucopolysaccharidosis, MPS-IV-B (1)

Mucopolysaccharidosis, MPS-IV-B (1)

Mucopolysaccharidosis, MPS-IV-B;C0268271:Infantile GM1 gangliosidosis;C0268272:GM1 gangliosidosis type 2;C0268273:GM1 gangliosidosis type 3 (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.090

BayesDel_addAF

Pathogenic

0.33

BayesDel_noAF

Pathogenic

0.46

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.63

Eigen

Pathogenic

0.72

Eigen_PC

Pathogenic

0.68

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.92

M_CAP

Uncertain

0.16

MetaRNN

Pathogenic

0.80

MetaSVM

Pathogenic

1.1

PhyloP100

7.5

PrimateAI

Uncertain

0.52

PROVEAN

Uncertain

-3.0

REVEL

Pathogenic

0.83

Sift

Benign

0.054

Sift4G

Benign

0.079

Vest4

0.84

MVP

0.99

MPC

0.97

ClinPred

0.64

GERP RS

5.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

gMVP

0.82

Mutation Taster

=4/96

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over