15-72345528-C-T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1PM2PP3_StrongPP5_Very_Strong

The NM_000520.6(HEXA):c.1444G>A(p.Glu482Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000743 in 1,614,102 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 Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 34)

Exomes 𝑓: 0.0000075 ( 0 hom. )

Consequence

HEXA
NM_000520.6 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6O:1

Conservation

PhyloP100: 7.49

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

HEXA links:

ENSG00000260729 (HGNC:):

ENSG00000260729 links:

ENSG00000261460 (HGNC:58304):

ENSG00000261460 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 16 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 13 uncertain in NM_000520.6

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.991

PP5

Variant 15-72345528-C-T is Pathogenic according to our data. Variant chr15-72345528-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 3892.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
HEXA	NM_000520.6 link	c.1444G>A	p.Glu482Lys	missense_variant	Exon 13 of 14	ENST00000268097.10	NP_000511.2	P06865-1A0A0S2Z3W3
HEXA	NM_001318825.2 link	c.1477G>A	p.Glu493Lys	missense_variant	Exon 13 of 14		NP_001305754.1	P06865H3BP20B4DVA7
HEXA	NR_134869.3 link	n.1229G>A		non_coding_transcript_exon_variant	Exon 11 of 11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HEXA	ENST00000268097.10 link	c.1444G>A	p.Glu482Lys	missense_variant	Exon 13 of 14	1	NM_000520.6	ENSP00000268097.6		P06865-1
ENSG00000260729	ENST00000379915.4 link	n.526G>A		non_coding_transcript_exon_variant	Exon 5 of 16	2		ENSP00000478716.1		A0A087WUJ7

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152240

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000795

AC:

AN:

251424

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000752

AC:

AN:

1461862

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727228

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53406

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000719

AC:

AN:

1112004

Other (OTH)

AF:

0.0000166

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.530

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<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:

0.00000657

AC:

AN:

152240

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74374

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41462

American (AMR)

AF:

0.00

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68048

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.000138

Hom.:

Bravo

AF:

0.0000264

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Tay-Sachs disease

Pathogenic:4Other:1

May 05, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: HEXA c.1444G>A (p.Glu482Lys) results in a conservative amino acid change located in the Glycoside hydrolase family 20, catalytic domain (IPR015883) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251424 control chromosomes. c.1444G>A has been reported in the literature as a homozygous genotype in multiple individuals affected with Tay-Sachs Disease and in settings of multigene panel testing for neurological disorders (example, Nakano_1988, Akli_1993 overlapping Poenaru_1994, Montalvo_2005, Ganapathy_2019). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function (Dersh_2019). The most pronounced variant effect results in abolishment of enzymatic activity against MUGS substrate, unprocessed by lysosomal proteases and altered folding as compared to the wild-type enzyme. This study also demonstrated that this variant retrotranslocated from the endoplasmic reticulum (ER) to the cytosol and was degraded by the proteasome, indicating clearance via ER-associated degradation (ERAD). The following publications have been ascertained in the context of this evaluation (PMID: 8490625, 27682588, 31069529, 16088929, 2970528, 7858168). Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Aug 01, 2008

OMIM

Significance:Affects

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Aug 14, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 482 of the HEXA protein (p.Glu482Lys). This variant is present in population databases (rs121907952, gnomAD 0.006%). This missense change has been observed in individual(s) with hexosaminidase A deficiency (PMID: 1301190, 2970528, 9338583, 16088929). ClinVar contains an entry for this variant (Variation ID: 3892). 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: 1301190, 8328462, 27682588). For these reasons, this variant has been classified as Pathogenic. -

Feb 10, 2016

Counsyl

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Jul 16, 2023

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with Tay-Sachs disease (MIM#272800). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from glutamic acid to lysine. (I) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD <0.01 for a recessive condition (v2: 2 heterozygotes, 0 homozygotes). (SP) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0600 - Variant is located in the annotated glycosyl hydrolase family 20, catalytic domain (DECIPHER). (I) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. It has been reported in at least two patients with Tay Sachs disease and has been classified as likely pathogenic and pathogenic by diagnostic laboratories (ClinVar; PMIDs: 1301190, 2970528, 16088929, 34800199, 31069529). (SP) 0905 - No published segregation evidence has been identified for this variant. (I) 1001 - This variant has strong functional evidence supporting abnormal protein function. Studies on patient fibroblasts demonstrated markedly reduced enzymatic activities and in vitro analysis demonstrated this is due to altered folding and inability to be secreted (PMID: 27682588). (SP) 1206 - This variant has been shown to be paternally inherited (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Inborn genetic diseases

Pathogenic:1

Aug 27, 2021

Ambry Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.1444G>A (p.E482K) alteration is located in exon 13 (coding exon 13) of the HEXA gene. This alteration results from a G to A substitution at nucleotide position 1444, causing the glutamic acid (E) at amino acid position 482 to be replaced by a lysine (K). Based on data from gnomAD, the A allele has an overall frequency of <0.01% (2/251424) total alleles studied. This alteration has been reported in patients with Tay-Sachs disease (Nakano, 1988; Montalvo, 2005). Based on internal structural analysis, this variant is highly destabilizing to the local structure (Novak, 1994; Hou, 1996; Hou, 1998; Hepbildikler, 2002; Lemieux, 2006). Enzymatic activity was undetectable in both cultured patient fibroblasts and cells transiently expressing p.E482K. In addition, p.E482K was severely misfolded and degraded by the proteosome (Brown, 1993; Dersh, 2016). This alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as likely pathogenic. -

not provided

Pathogenic:1

Dec 08, 2022

Mayo Clinic Laboratories, Mayo Clinic

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

PP3, PM2, PM3, PS3, PS4_moderate -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.96

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.60

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.98

D;.;D

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

1.0

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Pathogenic

1.0

D;D;D

M_CAP

Pathogenic

0.41

MetaRNN

Pathogenic

0.99

D;D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

4.5

H;.;.

PhyloP100

7.5

PrimateAI

Uncertain

0.60

PROVEAN

Uncertain

-3.7

D;D;D

REVEL

Pathogenic

0.95

Sift

Pathogenic

0.0

D;D;D

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0

D;.;.

Vest4

0.99

MutPred

0.98

Gain of MoRF binding (P = 0.0081);.;Gain of MoRF binding (P = 0.0081);

MVP

1.0

MPC

0.79

ClinPred

1.0

GERP RS

5.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.99

gMVP

1.0

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.060

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over