15-72350578-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_000520.6(HEXA):​c.745C>T​(p.Arg249Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000274 in 1,614,120 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 Conflicting classifications of pathogenicity,other (no stars).

Frequency

Genomes: 𝑓 0.00020 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00028 ( 0 hom. )

Consequence

HEXA
NM_000520.6 missense

Scores

11
7
1

Clinical Significance

Conflicting classifications of pathogenicity; other criteria provided, conflicting classifications U:1B:1O:3

Conservation

PhyloP100: 2.11
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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.927

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
HEXANM_000520.6 linkc.745C>T p.Arg249Trp missense_variant Exon 7 of 14 ENST00000268097.10 NP_000511.2 P06865-1A0A0S2Z3W3
HEXANM_001318825.2 linkc.778C>T p.Arg260Trp missense_variant Exon 7 of 14 NP_001305754.1 P06865H3BP20B4DVA7
HEXANR_134869.3 linkn.787C>T non_coding_transcript_exon_variant Exon 7 of 11

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
HEXAENST00000268097.10 linkc.745C>T p.Arg249Trp missense_variant Exon 7 of 14 1 NM_000520.6 ENSP00000268097.6 P06865-1
ENSG00000260729ENST00000379915.4 linkn.413-4253C>T intron_variant Intron 3 of 15 2 ENSP00000478716.1 A0A087WUJ7

Frequencies

GnomAD3 genomes
AF:
0.000204
AC:
31
AN:
152174
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.000121
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00135
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.000279
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.000191
AC:
48
AN:
251478
Hom.:
0
AF XY:
0.000199
AC XY:
27
AN XY:
135910
show subpopulations
Gnomad AFR exome
AF:
0.000123
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.000707
Gnomad SAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.000290
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.000282
AC:
412
AN:
1461828
Hom.:
0
Cov.:
31
AF XY:
0.000272
AC XY:
198
AN XY:
727218
show subpopulations
Gnomad4 AFR exome
AF:
0.000149
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.000579
Gnomad4 SAS exome
AF:
0.0000348
Gnomad4 FIN exome
AF:
0.0000187
Gnomad4 NFE exome
AF:
0.000304
Gnomad4 OTH exome
AF:
0.000696
GnomAD4 genome
AF:
0.000204
AC:
31
AN:
152292
Hom.:
0
Cov.:
32
AF XY:
0.000188
AC XY:
14
AN XY:
74482
show subpopulations
Gnomad4 AFR
AF:
0.000120
Gnomad4 AMR
AF:
0.00
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00135
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.000279
Gnomad4 OTH
AF:
0.00
Alfa
AF:
0.000333
Hom.:
1
Bravo
AF:
0.000246
TwinsUK
AF:
0.000270
AC:
1
ALSPAC
AF:
0.00
AC:
0
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000582
AC:
5
ExAC
AF:
0.000231
AC:
28
Asia WGS
AF:
0.000577
AC:
2
AN:
3478
EpiCase
AF:
0.000600
EpiControl
AF:
0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity; other
Submissions summary: Uncertain:1Benign:1Other:3
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:1Benign:1Other:1
other, criteria provided, single submitterclinical testingEurofins Ntd Llc (ga)Jul 19, 2016- Variant classified as "other reportable" ??? variant is clinically benign (not associated with disease) but is reported when observed (e.g. pseudodeficiency alleles).
Uncertain significance, criteria provided, single submitterclinical testingCeGaT Center for Human Genetics TuebingenFeb 01, 2024HEXA: PM2:Supporting -
Benign, criteria provided, single submitterclinical testingWomen's Health and Genetics/Laboratory Corporation of America, LabCorpAug 11, 2016Variant summary: The HEXA c.745C>T (p.Arg249Trp) variant causes a missense change involving a conserved nucleotide with 5/5 in silico tools predicting a damaging outcome. The variant of interest was found in the large, broad control population, ExAC, with an allele frequency of 28/121408 (1/4336), which does not exceed the estimated maximal expected allele frequency for a pathogenic HEXA variant of 1/715. The variant of interest is known to be a common pseudodeficiency allele, which is not associated with neurologic disease but is associated wtih reduced degradation of the synthetic substrate when HEX A enzymatic activity is determined (Gene Reviews). Therefore, the variant of interest is classified as Benign. -
Tay-Sachs disease Other:2
other, criteria provided, single submitterclinical testingLaboratory for Molecular Medicine, Mass General Brigham Personalized MedicineMay 30, 2014pseudodeficiency The Arg249Trp variant in HEXA is a well-established pseudodeficiency allele for HEXA activity (Cao 1993) and has been identified in 0.05% (5/8594) of European American chromosomes by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS/; dbSNP rs138058578). The Arg249Trp variant is clinically benign (i.e., has normal activity in vivo) but has reduced HEXA enzyme activity toward synthetic substrates and therefore can produce a false positive result on enzyme analysis, a technique often used for carrier screening (Hoffman 2013).
other, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpDec 13, 2018- pseudodeficiency allele

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.40
BayesDel_addAF
Pathogenic
0.28
D
BayesDel_noAF
Pathogenic
0.53
CADD
Pathogenic
29
DANN
Pathogenic
1.0
DEOGEN2
Pathogenic
0.98
D;.;D
Eigen
Uncertain
0.65
Eigen_PC
Uncertain
0.55
FATHMM_MKL
Uncertain
0.94
D
LIST_S2
Uncertain
0.96
D;D;D
M_CAP
Uncertain
0.25
D
MetaRNN
Pathogenic
0.93
D;D;D
MetaSVM
Pathogenic
1.1
D
MutationAssessor
Pathogenic
3.9
H;.;.
PrimateAI
Uncertain
0.64
T
PROVEAN
Pathogenic
-7.8
D;D;D
REVEL
Pathogenic
0.93
Sift
Pathogenic
0.0
D;D;D
Sift4G
Pathogenic
0.0
D;D;D
Polyphen
1.0
D;.;.
Vest4
0.88
MVP
1.0
MPC
0.73
ClinPred
0.95
D
GERP RS
5.0
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.1
Varity_R
0.92
gMVP
0.97

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

Below is the list of publications found by LitVar. It may be empty.

Other links and lift over

dbSNP: rs138058578; hg19: chr15-72642919; COSMIC: COSV99173798; COSMIC: COSV99173798; API