rs387906311

Variant names:

• chr15-72351132-C-A
• rs387906311
• ENST00000570175.1:n.2486C>A

Your query was ambiguous. Multiple possible variants found:

• chr15-72351132-C-A
• chr15-72351132-C-T

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM2 PP3_Strong PP5_Moderate

The ENST00000570175.1(ENSG00000261460):​n.2486C>A variant causes a non coding transcript exon change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000697 in 1,433,838 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 Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: ENSG00000261460 ENST00000570175.1 non_coding_transcript_exon
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.81
• Publications: 0 publications found

Genes affected

ENSG00000261460 (HGNC:58304):

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

ENSG00000260729 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 15-72351132-C-A is Pathogenic according to our data. Variant chr15-72351132-C-A is described in ClinVar as Pathogenic. ClinVar VariationId is 2914532.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HEXA	NM_000520.6	c.672+1G>T		splice_donor_variant, intron_variant	Intron 6 of 13	ENST00000268097.10	NP_000511.2
HEXA	NM_001318825.2	c.705+1G>T		splice_donor_variant, intron_variant	Intron 6 of 13		NP_001305754.1
HEXA	NR_134869.3	n.714+1G>T		splice_donor_variant, intron_variant	Intron 6 of 10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HEXA	ENST00000268097.10	c.672+1G>T		splice_donor_variant, intron_variant	Intron 6 of 13	1	NM_000520.6	ENSP00000268097.6
ENSG00000260729	ENST00000379915.4	n.412+4427G>T		intron_variant	Intron 3 of 15	2		ENSP00000478716.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.97e-7 AC: 1 AN: 1433838 Hom.: 0 Cov.: 27 AF XY: 0.00 AC XY: 0 AN XY: 715296

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 32904

American (AMR) AF: 0.00 AC: 0 AN: 44686

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25974

East Asian (EAS) AF: 0.00 AC: 0 AN: 39562

South Asian (SAS) AF: 0.00 AC: 0 AN: 85692

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5714

European-Non Finnish (NFE) AF: 9.20e-7 AC: 1 AN: 1086426

Other (OTH) AF: 0.00 AC: 0 AN: 59474

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tay-Sachs disease Pathogenic:1

Mar 17, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 6 of the HEXA gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with clinical features of hexosaminidase A deficiency (PMID: 14566483, 17015493). Studies have shown that disruption of this splice site results in skipping of exon 6, but is expected to preserve the integrity of the reading-frame (PMID: 8490625). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.45
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	1.0	D
PhyloP100		7.8
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.98		Position offset: 1

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

Other links and lift over

dbSNP: rs387906311; hg19: chr15-72643473; COSMIC: COSV51509016; COSMIC: COSV51509016;