NM_000405.5:c.37C>T

Variant names:

• chr5-151253253-C-T
• rs1753622145
• NM_000405.5:c.37C>T

Variant summary

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

The NM_000405.5(GM2A):​c.37C>T​(p.Leu13Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,740 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 (★). Synonymous variant affecting the same amino acid position (i.e. L13L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: GM2A NM_000405.5 synonymous
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.124
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• Tay-Sachs disease AB variant

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, ClinGen, Labcorp Genetics (formerly Invitae)

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=0.124 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000405.5. 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
	GM2A	NM_000405.5	MANE Select	c.37C>T	p.Leu13Leu	synonymous	Exon 1 of 4	NP_000396.2
	GM2A	NM_001167607.3		c.37C>T	p.Leu13Leu	synonymous	Exon 1 of 4	NP_001161079.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GM2A	ENST00000357164.4	TSL:1 MANE Select	c.37C>T	p.Leu13Leu	synonymous	Exon 1 of 4	ENSP00000349687.3	P17900
	GM2A	ENST00000937902.1		c.37C>T	p.Leu13Leu	synonymous	Exon 1 of 3	ENSP00000607961.1
	GM2A	ENST00000523466.5	TSL:3	c.127-6502C>T		intron	N/A	ENSP00000429100.1	E5RJD0

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461740 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727194

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53358

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1111926

Other (OTH) AF: 0.00 AC: 0 AN: 60392

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0404278), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000613 Hom.: 0

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Tay-Sachs disease, variant AB (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.62
CADD	Benign	8.5
DANN	Benign	0.79
PhyloP100		0.12
PromoterAI		-0.0080	Neutral

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

Other links and lift over

dbSNP: rs1753622145; hg19: chr5-150632814;