5-151253301-A-G

Position:

chr5-151253301-A-G

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2BP4_ModerateBS1_Supporting

The NM_000405.5(GM2A):c.81+4A>G variant causes a splice donor region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000535 in 1,606,134 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.00028 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000030 ( 0 hom. )

Consequence

GM2A
NM_000405.5 splice_donor_region, intron

Scores

Splicing: ADA: 0.8950

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.76

Variant links:

Genes affected

GM2A (HGNC:4367): (ganglioside GM2 activator) This gene encodes a small glycolipid transport protein which acts as a substrate specific co-factor for the lysosomal enzyme beta-hexosaminidase A. Beta-hexosaminidase A, together with GM2 ganglioside activator, catalyzes the degradation of the ganglioside GM2, and other molecules containing terminal N-acetyl hexosamines. Mutations in this gene result in GM2-gangliosidosis type AB or the AB variant of Tay-Sachs disease. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2009]

GM2A links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.39).

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000282 (43/152226) while in subpopulation AFR AF= 0.00104 (43/41544). AF 95% confidence interval is 0.000789. There are 0 homozygotes in gnomad4. There are 22 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GM2A	NM_000405.5 linkuse as main transcript	c.81+4A>G		splice_donor_region_variant, intron_variant		ENST00000357164.4
GM2A	NM_001167607.3 linkuse as main transcript	c.81+4A>G		splice_donor_region_variant, intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GM2A	ENST00000357164.4 linkuse as main transcript	c.81+4A>G		splice_donor_region_variant, intron_variant		1	NM_000405.5	P1
GM2A	ENST00000523466.5 linkuse as main transcript	c.127-6454A>G		intron_variant		3

Frequencies

GnomAD3 genomes

AF:

0.000276

AC:

AN:

152108

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00101

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:

0.0000518

AC:

AN:

250828

Hom.:

AF XY:

0.0000295

AC XY:

AN XY:

135654

show subpopulations

Gnomad AFR exome

AF:

0.000802

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000296

AC:

AN:

1453908

Hom.:

Cov.:

AF XY:

0.0000193

AC XY:

AN XY:

723834

show subpopulations

Gnomad4 AFR exome

AF:

0.00123

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000333

GnomAD4 genome

AF:

0.000282

AC:

AN:

152226

Hom.:

Cov.:

AF XY:

0.000296

AC XY:

AN XY:

74432

show subpopulations

Gnomad4 AFR

AF:

0.00104

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

Alfa

AF:

0.000254

Hom.:

Bravo

AF:

0.000280

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Tay-Sachs disease, variant AB

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 26, 2022

This sequence change falls in intron 1 of the GM2A gene. It does not directly change the encoded amino acid sequence of the GM2A protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs368443364, gnomAD 0.08%). This variant has not been reported in the literature in individuals affected with GM2A-related conditions. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.39

CADD

Benign

DANN

Benign

0.79

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.89

dbscSNV1_RF

Benign

0.51

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