Genetic Variant GLB1:p.Arg68Trp (chr3-33072587-G-A) – ACMG Classification: Pathogenic (15 pts)

Variant summary

Our verdict is Pathogenic. The variant received 15 ACMG points: 15P and 0B. PM2PM5PP2PP3_ModeratePP5_Very_Strong

The NM_001317040.2(GLB1):c.346C>T(p.Arg116Trp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000248 in 1,613,844 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R116L) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000025 ( 0 hom. )

Consequence

GLB1
NM_001317040.2 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:6

Conservation

PhyloP100: 8.13

Publications

16 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

GLB1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 15 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr3-33072586-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1482642.

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: 0.88447 (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, 0.938

PP5

Variant 3-33072587-G-A is Pathogenic according to our data. Variant chr3-33072587-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 944.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001317040.2. 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.202C>T	p.Arg68Trp	missense	Exon 2 of 16	NP_000395.3
GLB1	NM_001317040.2		c.346C>T	p.Arg116Trp	missense	Exon 3 of 17	NP_001303969.2
GLB1	NM_001079811.3		c.112C>T	p.Arg38Trp	missense	Exon 2 of 16	NP_001073279.2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
GLB1	ENST00000307363.10	TSL:1 MANE Select	c.202C>T	p.Arg68Trp	missense	Exon 2 of 16	ENSP00000306920.4
GLB1	ENST00000307377.12	TSL:1	c.202C>T	p.Arg68Trp	missense	Exon 2 of 13	ENSP00000305920.8
GLB1	ENST00000399402.7	TSL:2	c.112C>T	p.Arg38Trp	missense	Exon 2 of 16	ENSP00000382333.2

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152180

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:

0.0000942

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000281

AC:

AN:

249454

AF XY:

0.0000369

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 FIN exome

AF:

0.000186

Gnomad NFE exome

AF:

0.0000177

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000246

AC:

AN:

1461664

Hom.:

Cov.:

AF XY:

0.0000220

AC XY:

AN XY:

727128

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33474

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86234

European-Finnish (FIN)

AF:

0.000131

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5598

European-Non Finnish (NFE)

AF:

0.0000252

AC:

AN:

1112010

Other (OTH)

AF:

0.00

AC:

AN:

60372

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

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:

0.0000263

AC:

AN:

152180

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74344

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41434

American (AMR)

AF:

0.00

AC:

AN:

15274

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.0000942

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68040

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

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:

0.0000283

Hom.:

Bravo

AF:

0.0000227

ExAC

AF:

0.0000331

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

ClinVar submissions as Germline

Significance:Pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

GM1 gangliosidosis type 2 (1)

GM1 gangliosidosis type 3 (1)

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

Infantile GM1 gangliosidosis (1)

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

not provided (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.55

BayesDel_addAF

Pathogenic

0.51

BayesDel_noAF

Pathogenic

0.60

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.86

Eigen

Pathogenic

0.96

Eigen_PC

Pathogenic

0.86

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Pathogenic

1.0

M_CAP

Pathogenic

0.53

MetaRNN

Pathogenic

0.94

MetaSVM

Pathogenic

1.0

PhyloP100

8.1

PrimateAI

Uncertain

0.76

PROVEAN

Pathogenic

-7.2

REVEL

Pathogenic

0.98

Sift

Uncertain

0.0010

Sift4G

Pathogenic

0.0010

Polyphen

1.0

Vest4

0.92

MVP

1.0

MPC

0.89

ClinPred

1.0

GERP RS

4.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.8

gMVP

0.98

Mutation Taster

=2/98

disease causing (ClinVar)

(source)

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

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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