rs786204744

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000520.6(HEXA):c.1123delG(p.Glu375ArgfsTer7) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,612,106 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

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

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

HEXA
NM_000520.6 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8

Conservation

PhyloP100: 7.74

Publications

2 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 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 15-72347708-TC-T is Pathogenic according to our data. Variant chr15-72347708-TC-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 189166.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.1123delG	p.Glu375ArgfsTer7	frameshift_variant	Exon 10 of 14	ENST00000268097.10	NP_000511.2	P06865-1A0A0S2Z3W3
HEXA	NM_001318825.2 link	c.1156delG	p.Glu386ArgfsTer7	frameshift_variant	Exon 10 of 14		NP_001305754.1	P06865H3BP20B4DVA7
HEXA	NR_134869.3 link	n.1115+339delG		intron_variant	Intron 9 of 10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HEXA	ENST00000268097.10 link	c.1123delG	p.Glu375ArgfsTer7	frameshift_variant	Exon 10 of 14	1	NM_000520.6	ENSP00000268097.6		P06865-1
ENSG00000260729	ENST00000379915.4 link	n.413-1384delG		intron_variant	Intron 3 of 15	2		ENSP00000478716.1		A0A087WUJ7

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152076

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000812

AC:

AN:

246288

AF XY:

0.0000149

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:

0.0000180

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1460030

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726296

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33466

American (AMR)

AF:

0.00

AC:

AN:

44644

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39636

South Asian (SAS)

AF:

0.00

AC:

AN:

86244

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52256

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.00000270

AC:

AN:

1111684

Other (OTH)

AF:

0.0000166

AC:

AN:

60206

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152076

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74270

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41418

American (AMR)

AF:

0.00

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10586

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68004

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.0000113

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Tay-Sachs disease

Pathogenic:6

Jan 01, 2019

Institute of Human Genetics, University of Leipzig Medical Center

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Apr 11, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Glu375Argfs*7) in the HEXA gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in HEXA are known to be pathogenic (PMID: 1833974, 8490625). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This premature translational stop signal has been observed in individual(s) with Tay-Sachs disease (PMID: 16088929, 31076878). ClinVar contains an entry for this variant (Variation ID: 189166). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Jan 30, 2015

Counsyl

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

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. -

Nov 25, 2019

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.1123delG (p.Glu375ArgfsX7) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 8.1e-06 in 246288 control chromosomes. c.1123delG has been reported in the literature in individuals affected with Tay-Sachs Disease (example, Montalvo_2005, Jamrozik_2013, Jahnova_2019). These data indicate that the variant is likely to be associated with disease. No experimental evidence demonstrating an impact on protein function were ascertained in the context of this evaluation. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Mar 16, 2017

Natera, Inc.

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Feb 09, 2022

MGZ Medical Genetics Center

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:2

Oct 23, 2020

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Apr 04, 2023

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This frameshift variant alters the translational reading frame of the HEXA mRNA and causes the premature termination of HEXA protein synthesis. In the published literature, the variant has been reported as compound heterozygous with other pathogenic variants in individuals with Tay-Sachs Disease (PMIDs: 16088929 (2005), 23820084 (2013), and 31076878 (2019)). Based on the available information, this variant is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

7.7

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over