rs121907958

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM2PP3_StrongPP5_Very_Strong

The NM_000520.6(HEXA):​c.1260G>C​(p.Trp420Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000248 in 1,613,938 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 30)
Exomes 𝑓: 0.000025 ( 0 hom. )

Consequence

HEXA
NM_000520.6 missense

Scores

14
4
1

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:2O:1

Conservation

PhyloP100: 7.78

Publications

9 publications found
Variant links:
Genes affected
HEXA (HGNC:4878): (hexosaminidase subunit alpha) This gene encodes a member of the glycosyl hydrolase 20 family of proteins. The encoded preproprotein is proteolytically processed to generate the alpha subunit of the lysosomal enzyme beta-hexosaminidase. This enzyme, together with the cofactor GM2 activator protein, catalyzes the degradation of the ganglioside GM2, and other molecules containing terminal N-acetyl hexosamines. Mutations in this gene lead to an accumulation of GM2 ganglioside in neurons, the underlying cause of neurodegenerative disorders termed the GM2 gangliosidoses, including Tay-Sachs disease (GM2-gangliosidosis type I). Alternative splicing results in multiple transcript variants, at least one of which encodes a preproprotein that is proteolytically processed. [provided by RefSeq, Jan 2016]
HEXA Gene-Disease associations (from GenCC):
  • Tay-Sachs disease
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Myriad Women’s Health, Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae), ClinGen

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 14 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.985
PP5
Variant 15-72346597-C-G is Pathogenic according to our data. Variant chr15-72346597-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 3901.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
HEXANM_000520.6 linkc.1260G>C p.Trp420Cys missense_variant Exon 11 of 14 ENST00000268097.10 NP_000511.2 P06865-1A0A0S2Z3W3
HEXANM_001318825.2 linkc.1293G>C p.Trp431Cys missense_variant Exon 11 of 14 NP_001305754.1 P06865H3BP20B4DVA7
HEXANR_134869.3 linkn.1116-272G>C intron_variant Intron 9 of 10

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
HEXAENST00000268097.10 linkc.1260G>C p.Trp420Cys missense_variant Exon 11 of 14 1 NM_000520.6 ENSP00000268097.6 P06865-1
ENSG00000260729ENST00000379915.4 linkn.413-272G>C intron_variant Intron 3 of 15 2 ENSP00000478716.1 A0A087WUJ7

Frequencies

GnomAD3 genomes
AF:
0.0000263
AC:
4
AN:
152126
Hom.:
0
Cov.:
30
show subpopulations
Gnomad AFR
AF:
0.0000483
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:
0.00000795
AC:
2
AN:
251462
AF XY:
0.00
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000176
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000246
AC:
36
AN:
1461812
Hom.:
0
Cov.:
34
AF XY:
0.0000234
AC XY:
17
AN XY:
727216
show subpopulations
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:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86254
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53418
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5732
European-Non Finnish (NFE)
AF:
0.0000306
AC:
34
AN:
1111974
Other (OTH)
AF:
0.0000331
AC:
2
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.451
Heterozygous variant carriers
0
2
4
7
9
11
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome 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
GnomAD4 genome
AF:
0.0000263
AC:
4
AN:
152126
Hom.:
0
Cov.:
30
AF XY:
0.0000269
AC XY:
2
AN XY:
74302
show subpopulations
African (AFR)
AF:
0.0000483
AC:
2
AN:
41414
American (AMR)
AF:
0.00
AC:
0
AN:
15260
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5188
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4822
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10618
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000294
AC:
2
AN:
68036
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.513
Heterozygous variant carriers
0
1
1
2
2
3
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:
0.0000675
Hom.:
0
Bravo
AF:
0.0000378
TwinsUK
AF:
0.00
AC:
0
ALSPAC
AF:
0.000259
AC:
1
ExAC
AF:
0.00000824
AC:
1
EpiCase
AF:
0.00
EpiControl
AF:
0.0000593

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:2Other:1
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Tay-Sachs disease Pathogenic:1Other:1
Oct 12, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces tryptophan, which is neutral and slightly polar, with cysteine, which is neutral and slightly polar, at codon 420 of the HEXA protein (p.Trp420Cys). This variant is present in population databases (rs121907958, gnomAD 0.003%). This missense change has been observed in individual(s) with HEXA-related conditions (PMID: 2144098, 14566483; internal data). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 3901). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt HEXA protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects HEXA function (PMID: 2144098). For these reasons, this variant has been classified as Pathogenic. -

Sep 01, 1990
OMIM
Significance:Affects
Review Status:no assertion criteria provided
Collection Method:literature only

- -

not provided Pathogenic:1
Mar 14, 2025
GeneDx
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Published functional studies demonstrate the W420C variant results in a non-functional protein (PMID: 2144098, 18490185); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 14566483, 18490185, 2144098) -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.97
BayesDel_addAF
Pathogenic
0.51
D
BayesDel_noAF
Pathogenic
0.51
CADD
Pathogenic
28
DANN
Uncertain
0.99
DEOGEN2
Pathogenic
0.96
D;.;D
Eigen
Pathogenic
0.90
Eigen_PC
Pathogenic
0.89
FATHMM_MKL
Pathogenic
1.0
D
LIST_S2
Pathogenic
0.99
D;D;D
M_CAP
Uncertain
0.22
D
MetaRNN
Pathogenic
0.99
D;D;D
MetaSVM
Pathogenic
0.99
D
MutationAssessor
Uncertain
2.3
M;.;.
PhyloP100
7.8
PrimateAI
Uncertain
0.65
T
PROVEAN
Pathogenic
-12
D;D;D
REVEL
Pathogenic
0.88
Sift
Pathogenic
0.0
D;D;D
Sift4G
Pathogenic
0.0
D;D;D
Polyphen
1.0
D;.;.
Vest4
0.95
MutPred
0.90
Gain of catalytic residue at P419 (P = 0.0088);.;Gain of catalytic residue at P419 (P = 0.0088);
MVP
1.0
MPC
0.95
ClinPred
1.0
D
GERP RS
5.9
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.99
gMVP
0.98
Mutation Taster
=0/100
disease causing (ClinVar)

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: rs121907958; hg19: chr15-72638938; API