chr15-72350569-G-A

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong

The NM_000520.6(HEXA):c.754C>T(p.Arg252Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,614,066 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R252H) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000048 ( 0 hom. )

Consequence

HEXA
NM_000520.6 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:9U:1

Conservation

PhyloP100: 1.59

Publications

6 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:

ENSG00000261460 (HGNC:58304):

ENSG00000261460 links:

ENSG00000260729 (HGNC:):

ENSG00000260729 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 9 uncertain in NM_000520.6

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr15-72350568-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 1074825.Status of the report is criteria_provided_single_submitter, 1 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.962

PP5

Variant 15-72350569-G-A is Pathogenic according to our data. Variant chr15-72350569-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 522667.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
HEXA	NM_000520.6 link	c.754C>T	p.Arg252Cys	missense_variant	Exon 7 of 14	ENST00000268097.10	NP_000511.2
HEXA	NM_001318825.2 link	c.787C>T	p.Arg263Cys	missense_variant	Exon 7 of 14		NP_001305754.1
HEXA	NR_134869.3 link	n.796C>T		non_coding_transcript_exon_variant	Exon 7 of 11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HEXA	ENST00000268097.10 link	c.754C>T	p.Arg252Cys	missense_variant	Exon 7 of 14	1	NM_000520.6	ENSP00000268097.6
ENSG00000260729	ENST00000379915.4 link	n.413-4244C>T		intron_variant	Intron 3 of 15	2		ENSP00000478716.1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152124

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000119

AC:

AN:

251466

AF XY:

0.0000221

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:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000479

AC:

AN:

1461824

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727220

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5742

European-Non Finnish (NFE)

AF:

0.00000450

AC:

AN:

1111988

Other (OTH)

AF:

0.00

AC:

AN:

60388

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.461

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:

0.0000197

AC:

AN:

152242

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74446

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41528

American (AMR)

AF:

0.0000654

AC:

AN:

15294

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.000415

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10602

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68020

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.458

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.0000247

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:9Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Tay-Sachs disease

Pathogenic:8Uncertain:1

Jul 05, 2019

Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:research

Nov 01, 2021

Myriad Genetics, Inc.

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

NM_000520.4(HEXA):c.754C>T(R252C) is a missense variant classified as likely pathogenic in the context of hexosaminidase A deficiency. R252C has been observed in cases with relevant disease (PMID: 31076878, 31388111, 33240792). Functional assessments of this variant are not available in the literature. R252C has been observed in population frequency databases (gnomAD: SAS 0.01%). In summary, NM_000520.4(HEXA):c.754C>T(R252C) is a missense variant that has been observed more frequently in cases with the relevant disease than in healthy populations. Please note: this variant was assessed in the context of healthy population screening.

Dec 03, 2017

Genomic Research Center, Shahid Beheshti University of Medical Sciences

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Mar 02, 2020

Revvity Omics, Revvity

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Sep 16, 2020

Natera, Inc.

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

Sep 29, 2021

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.754C>T (p.Arg252Cys) results in a non-conservative amino acid change located in the Glycoside hydrolase family 20, catalytic domain (IPR015883) of the encoded protein sequence. Other missense variant affecting this residue, such as p.Arg252His and p.Arg252Leu have been reported in patients with Tay-Sachs disease, supporting a critical role for this residue for overall function. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 251466 control chromosomes. c.754C>T has been reported in the literature as a homozygous and compound heterozygous genotype in multiple individuals affected with Tay-Sachs Disease (example, Mistri_2019, Jahnova_2019, King_2020, Mahdieh_2021). 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. The most pronounced variant effect results in <10% of normal HEX-A activity with MUGS as a substrate (example, Mistri_2019). Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation (likely pathogenic, n=4, VUS, n=1). None of these submitters cite overlapping evidence utilized in the context of this evaluation. Based on the evidence outlined above, the variant was classified as pathogenic.

Sep 30, 2022

Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The variant has shown a homozygous status for c.754C>T (p.Arg252Cys) in exon 7 of the HEXA gene. This variant is not reported in the 1000 genomes and has MAF of 0.0019% in the gnomAD database. It is reported in dbSNP database with ID of rs566580738. The in-silico prediction of the variant is disease causing by LRT, MutPred, Mutation Taster, SIFT and PROVEAN.

Oct 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 252 of the HEXA protein (p.Arg252Cys). This variant is present in population databases (rs566580738, gnomAD 0.006%). This missense change has been observed in individual(s) with HEXA-related diseases (PMID: 31076878; internal data). ClinVar contains an entry for this variant (Variation ID: 522667). 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%. This variant disrupts the p.Arg252 amino acid residue in HEXA. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 8730294). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic.

Myelin Disorders Clinic-Children's Medical Center/Medical Genetics Lab-Tarbiat Modares University, Children's Medical Center, Pediatrics Center of Excellence,

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

not provided

Pathogenic:1

Jul 15, 2024

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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: 8730294, 33547378, 33240792, 31388111, 38277958, 38168508, 31076878)

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.71

BayesDel_addAF

Pathogenic

0.42

BayesDel_noAF

Pathogenic

0.55

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.98

D;.;D

Eigen

Pathogenic

0.94

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Uncertain

0.94

LIST_S2

Pathogenic

1.0

D;D;D

M_CAP

Uncertain

0.16

MetaRNN

Pathogenic

0.96

D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.2

H;.;.

PhyloP100

1.6

PrimateAI

Uncertain

0.65

PROVEAN

Pathogenic

-7.8

D;D;D

REVEL

Pathogenic

0.89

Sift

Pathogenic

0.0

D;D;D

Sift4G

Pathogenic

0.0010

D;D;D

Vest4

0.96

ClinPred

1.0

GERP RS

4.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.97

gMVP

0.94

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

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

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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