NM_000404.4:c.1746G>T

Variant names:

• chr3-32997333-C-A
• rs778375259
• NM_000404.4:c.1746G>T

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1 PM2 PP2 PP3_Moderate

The NM_000404.4(GLB1):​c.1746G>T​(p.Trp582Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,754 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/20 in silico tools predict a damaging outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GLB1 NM_000404.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.86
• Publications: 0 publications found

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

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM1: In a hotspot region, there are 8 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
• 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, 0.916

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GLB1	NM_000404.4	MANE Select	c.1746G>T	p.Trp582Cys	missense	Exon 16 of 16	NP_000395.3
	GLB1	NM_001317040.2		c.1890G>T	p.Trp630Cys	missense	Exon 17 of 17	NP_001303969.2
	GLB1	NM_001079811.3		c.1656G>T	p.Trp552Cys	missense	Exon 16 of 16	NP_001073279.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GLB1	ENST00000307363.10	TSL:1 MANE Select	c.1746G>T	p.Trp582Cys	missense	Exon 16 of 16	ENSP00000306920.4	P16278
	GLB1	ENST00000307377.12	TSL:1	c.1353G>T	p.Trp451Cys	missense	Exon 13 of 13	ENSP00000305920.8	E7EQ29
	GLB1	ENST00000399402.7	TSL:2	c.1656G>T	p.Trp552Cys	missense	Exon 16 of 16	ENSP00000382333.2	P16278

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460754 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726656

African (AFR) AF: 0.00 AC: 0 AN: 33442

American (AMR) AF: 0.00 AC: 0 AN: 44714

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86200

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53410

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4956

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111922

Other (OTH) AF: 0.00 AC: 0 AN: 60278

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.49	D
MetaRNN	Pathogenic	0.92	D
MetaSVM	Pathogenic	1.1	D
PhyloP100		7.9
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-7.1	D
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0030	D
Sift4G	Uncertain	0.0040	D
Polyphen		1.0	D
Vest4		0.93
MutPred		0.70		Loss of MoRF binding (P = 0.0363)
MVP		0.98
MPC		1.1
ClinPred		1.0	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
gMVP		0.94
Mutation Taster		=9/91	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs778375259; hg19: chr3-33038825; COSMIC: COSV56568868;