15-72349147-TAAG-T

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2PM4_SupportingPP5_Very_Strong

The NM_000520.6(HEXA):c.915_917delCTT(p.Phe305del) variant causes a disruptive inframe deletion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000663 in 1,614,014 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000068 ( 0 hom. )

Consequence

HEXA
NM_000520.6 disruptive_inframe_deletion

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 2.51

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 links:

ENSG00000260729 (HGNC:):

ENSG00000260729 links:

ENSG00000261460 (HGNC:58304):

ENSG00000261460 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 11 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM4

Nonframeshift variant in NON repetitive region in NM_000520.6. Strenght limited to Supporting due to length of the change: 1aa.

PP5

Variant 15-72349147-TAAG-T is Pathogenic according to our data. Variant chr15-72349147-TAAG-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 188812.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr15-72349147-TAAG-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HEXA	NM_000520.6 link	c.915_917delCTT	p.Phe305del	disruptive_inframe_deletion	Exon 8 of 14	ENST00000268097.10	NP_000511.2	P06865-1A0A0S2Z3W3
HEXA	NM_001318825.2 link	c.948_950delCTT	p.Phe316del	disruptive_inframe_deletion	Exon 8 of 14		NP_001305754.1	P06865H3BP20B4DVA7
HEXA	NR_134869.3 link	n.957_959delCTT		non_coding_transcript_exon_variant	Exon 8 of 11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HEXA	ENST00000268097.10 link	c.915_917delCTT	p.Phe305del	disruptive_inframe_deletion	Exon 8 of 14	1	NM_000520.6	ENSP00000268097.6		P06865-1
ENSG00000260729	ENST00000379915.4 link	n.413-2825_413-2823delCTT		intron_variant	Intron 3 of 15	2		ENSP00000478716.1		A0A087WUJ7

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152168

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:

0.000282

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000676

AC:

AN:

251444

Hom.:

AF XY:

0.0000589

AC XY:

AN XY:

135894

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000867

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.000323

Gnomad NFE exome

AF:

0.0000615

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000677

AC:

AN:

1461728

Hom.:

AF XY:

0.0000701

AC XY:

AN XY:

727198

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000894

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.000262

Gnomad4 NFE exome

AF:

0.0000693

Gnomad4 OTH exome

AF:

0.0000662

GnomAD4 genome

AF:

0.0000525

AC:

AN:

152286

Hom.:

Cov.:

AF XY:

0.0000537

AC XY:

AN XY:

74462

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.000282

Gnomad4 NFE

AF:

0.0000735

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000226

Hom.:

Bravo

AF:

0.0000227

EpiCase

AF:

0.0000545

EpiControl

AF:

0.000119

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Tay-Sachs disease

Pathogenic:5

Jun 05, 2014

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: literature only

- -

Jan 28, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant, c.915_917del, results in the deletion of 1 amino acid(s) of the HEXA protein (p.Phe305del), but otherwise preserves the integrity of the reading frame. This variant is present in population databases (rs778155650, gnomAD 0.03%). This variant has been observed in individual(s) with Tay-Sachs disease (PMID: 1322637, 1825014, 1837283, 16088929). It is commonly reported in individuals of Moroccan ancestry (PMID: 1322637, 1825014). This variant is also known as p.F304del. ClinVar contains an entry for this variant (Variation ID: 188812). Algorithms developed to predict the effect of variants on gene product structure and function are not available or were not evaluated for this variant. Experimental studies have shown that this variant affects HEXA function (PMID: 1825014). For these reasons, this variant has been classified as Pathogenic. -

Aug 16, 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.915_917delCTT (p.Phe305del) results in an in-frame deletion that is predicted to remove one amino acid from the encoded protein. The variant allele was found at a frequency of 6.8e-05 in 251444 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in HEXA causing Tay-Sachs Disease (6.8e-05 vs 0.0014), allowing no conclusion about variant significance. c.915_917delCTT has been reported in the literature in multiple individuals affected with Tay-Sachs Disease, and has been reported as a common mutation in the Moroccan population (Navon_1991, Akli_1991, Montalvo_2005). 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 variant was reported to render the alpha-subunit enzymatically inactive (Montalvo_2005). Three 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. Based on the evidence outlined above, the variant was classified as pathogenic. -

Aug 01, 1992

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Mar 17, 2017

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Inborn genetic diseases

Pathogenic:1

Jul 25, 2017

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Pathogenic:1

Nov 12, 2024

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Transfection in COS-1 cells of the mutant protein demonstrated an impairment in the alpha subunit of beta-hexosaminidase A, resulting in an absence of enzyme activity (PMID: 1825014); In-frame deletion of 1 amino acid in a non-repeat region predicted to critically alter the protein; In silico analysis supports a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 1322637, 16088929, 22789865, 1837283, 1825014) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

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.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over