3-32997255-C-A

Variant names:

• chr3-32997255-C-A
• NM_000404.4:c.1824G>T
• GLB1 p.Leu608Leu

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_000404.4(GLB1):​c.1824G>T​(p.Leu608Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. L608L) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GLB1 NM_000404.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.172
• 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_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.62).
• BP7: Synonymous conserved (PhyloP=0.172 with no splicing effect.

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.1824G>T	p.Leu608Leu	synonymous	Exon 16 of 16	NP_000395.3
	GLB1	NM_001317040.2		c.1968G>T	p.Leu656Leu	synonymous	Exon 17 of 17	NP_001303969.2
	GLB1	NM_001079811.3		c.1734G>T	p.Leu578Leu	synonymous	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.1824G>T	p.Leu608Leu	synonymous	Exon 16 of 16	ENSP00000306920.4	P16278
	GLB1	ENST00000307377.12	TSL:1	c.1431G>T	p.Leu477Leu	synonymous	Exon 13 of 13	ENSP00000305920.8	E7EQ29
	GLB1	ENST00000399402.7	TSL:2	c.1734G>T	p.Leu578Leu	synonymous	Exon 16 of 16	ENSP00000382333.2	P16278

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.62
CADD	Benign	7.1
DANN	Benign	0.48
PhyloP100		0.17

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr3-33038747;