rs104893892

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM5BP4_ModerateBS1_Supporting

The NM_000405.5(GM2A):​c.506G>A​(p.Arg169His) variant causes a missense change. The variant allele was found at a frequency of 0.0000774 in 1,614,172 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R169P) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.00022 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000063 ( 0 hom. )

Consequence

GM2A
NM_000405.5 missense

Scores

7
12

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 6.15

Publications

7 publications found
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 Gene-Disease associations (from GenCC):
  • Tay-Sachs disease AB variant
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae), ClinGen

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -1 ACMG points.

PM5
Other missense variant is known to change same aminoacid residue: Variant chr5-151267375-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 391.Status of the report is no_assertion_criteria_provided, 0 stars.
BP4
Computational evidence support a benign effect (MetaRNN=0.17699257).
BS1
Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.000217 (33/152288) while in subpopulation AFR AF = 0.000746 (31/41562). AF 95% confidence interval is 0.000539. There are 0 homozygotes in GnomAd4. There are 15 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
GM2ANM_000405.5 linkc.506G>A p.Arg169His missense_variant Exon 4 of 4 ENST00000357164.4 NP_000396.2
GM2ANM_001167607.3 linkc.413-117G>A intron_variant Intron 3 of 3 NP_001161079.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
GM2AENST00000357164.4 linkc.506G>A p.Arg169His missense_variant Exon 4 of 4 1 NM_000405.5 ENSP00000349687.3
GM2AENST00000523004.1 linkc.*450G>A downstream_gene_variant 1 ENSP00000430541.1

Frequencies

GnomAD3 genomes
AF:
0.000204
AC:
31
AN:
152170
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.000700
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:
0.0000294
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000955
AC:
24
AN:
251366
AF XY:
0.0000810
show subpopulations
Gnomad AFR exome
AF:
0.00105
Gnomad AMR exome
AF:
0.0000867
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000352
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000629
AC:
92
AN:
1461884
Hom.:
0
Cov.:
35
AF XY:
0.0000564
AC XY:
41
AN XY:
727242
show subpopulations
African (AFR)
AF:
0.000687
AC:
23
AN:
33480
American (AMR)
AF:
0.0000894
AC:
4
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.0000756
AC:
3
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53420
Middle Eastern (MID)
AF:
0.000173
AC:
1
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000504
AC:
56
AN:
1112006
Other (OTH)
AF:
0.0000828
AC:
5
AN:
60396
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.470
Heterozygous variant carriers
0
6
11
17
22
28
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
4
8
12
16
20
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.000217
AC:
33
AN:
152288
Hom.:
0
Cov.:
32
AF XY:
0.000201
AC XY:
15
AN XY:
74472
show subpopulations
African (AFR)
AF:
0.000746
AC:
31
AN:
41562
American (AMR)
AF:
0.00
AC:
0
AN:
15302
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5182
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4822
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10620
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000294
AC:
2
AN:
68008
Other (OTH)
AF:
0.00
AC:
0
AN:
2116
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.465
Heterozygous variant carriers
0
2
3
5
6
8
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.000135
Hom.:
0
Bravo
AF:
0.000295
ESP6500AA
AF:
0.000908
AC:
4
ESP6500EA
AF:
0.00
AC:
0
ExAC
AF:
0.0000988
AC:
12
Asia WGS
AF:
0.000289
AC:
1
AN:
3478
EpiCase
AF:
0.00
EpiControl
AF:
0.000119

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Tay-Sachs disease, variant AB Uncertain:1
Aug 31, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 169 of the GM2A protein (p.Arg169His). This variant is present in population databases (rs104893892, gnomAD 0.09%). This variant has not been reported in the literature in individuals affected with GM2A-related conditions. ClinVar contains an entry for this variant (Variation ID: 1350409). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C25"). 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. -

Inborn genetic diseases Uncertain:1
Jul 14, 2021
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The c.506G>A (p.R169H) alteration is located in exon 4 (coding exon 4) of the GM2A gene. This alteration results from a G to A substitution at nucleotide position 506, causing the arginine (R) at amino acid position 169 to be replaced by a histidine (H). 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
0.12
BayesDel_addAF
Benign
-0.23
T
BayesDel_noAF
Benign
-0.16
CADD
Benign
22
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.60
D
Eigen
Benign
0.0027
Eigen_PC
Benign
0.040
FATHMM_MKL
Uncertain
0.95
D
LIST_S2
Benign
0.72
T
M_CAP
Uncertain
0.093
D
MetaRNN
Benign
0.18
T
MetaSVM
Benign
-0.51
T
MutationAssessor
Uncertain
2.4
M
PhyloP100
6.2
PrimateAI
Benign
0.35
T
PROVEAN
Uncertain
-3.3
D
REVEL
Uncertain
0.36
Sift
Benign
0.063
T
Sift4G
Benign
0.11
T
Polyphen
0.47
P
Vest4
0.42
MVP
0.77
MPC
0.12
ClinPred
0.097
T
GERP RS
4.4
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.1
Varity_R
0.56
gMVP
0.72
Mutation Taster
=38/62
disease causing

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

Other links and lift over

dbSNP: rs104893892; hg19: chr5-150646936; COSMIC: COSV64095931; COSMIC: COSV64095931; API