5-151253230-T-C

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BS1_Supporting

The NM_000405.5(GM2A):c.14T>C(p.Met5Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000793 in 1,614,030 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M5L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000039 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000083 (0 hom.)
• Consequence: GM2A NM_000405.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.192

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]

ACMG classification

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 (MetaRNN=0.07887599).
• BS1: Variant frequency is greater than expected in population nfe. gnomad4_exome allele frequency = 0.0000835 (122/1461706) while in subpopulation NFE AF= 0.000103 (115/1111872). AF 95% confidence interval is 0.0000876. There are 0 homozygotes in gnomad4_exome. There are 54 alleles in male gnomad4_exome subpopulation. Median coverage is 31. 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	c.14T>C	p.Met5Thr	missense_variant	1/4	ENST00000357164.4
GM2A	NM_001167607.3	c.14T>C	p.Met5Thr	missense_variant	1/4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GM2A	ENST00000357164.4	c.14T>C	p.Met5Thr	missense_variant	1/4	1	NM_000405.5	P1
GM2A	ENST00000523466.5	c.127-6525T>C		intron_variant		3

Frequencies

GnomAD3 genomes AF: 0.0000394 AC: 6 AN: 152206 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000193

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000239 AC: 6 AN: 251434 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135896

Gnomad AFR exome AF: 0.0000615

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: 0.0000440

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000835 AC: 122 AN: 1461706 Hom.: 0 Cov.: 31 AF XY: 0.0000743 AC XY: 54 AN XY: 727170

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000504

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000375

Gnomad4 NFE exome AF: 0.000103

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.0000394 AC: 6 AN: 152324 Hom.: 0 Cov.: 32 AF XY: 0.0000403 AC XY: 3 AN XY: 74482

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000193

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000508 Hom.: 0

Bravo AF: 0.0000416

ExAC AF: 0.0000247 AC: 3

Asia WGS AF: 0.000289 AC: 1 AN: 3478

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 08, 2023

The c.14T>C (p.M5T) alteration is located in exon 1 (coding exon 1) of the GM2A gene. This alteration results from a T to C substitution at nucleotide position 14, causing the methionine (M) at amino acid position 5 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Benign	-0.31	T
BayesDel_noAF	Benign	-0.50
Cadd	Benign	12
Dann	Benign	0.68
DEOGEN2	Benign	0.15	T
Eigen	Benign	-0.94
Eigen_PC	Benign	-1.0
FATHMM_MKL	Benign	0.11	N
LIST_S2	Benign	0.37	T
M_CAP	Benign	0.021	T
MetaRNN	Benign	0.079	T
MetaSVM	Benign	-0.95	T
MutationAssessor	Benign	1.4	L
MutationTaster	Benign	1.0	N
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-1.6	N
REVEL	Benign	0.064
Sift	Uncertain	0.0030	D
Sift4G	Benign	0.20	T
Polyphen		0.0050	B
Vest4		0.12
MVP		0.44
MPC		0.077
ClinPred		0.19	T
GERP RS		0.73
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.50
gMVP		0.56

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

LitVar

Other links and lift over

dbSNP: rs759249002; hg19: chr5-150632791;