rs121907952

chr15-72345528-C-Achr15-72345528-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_000520.6(HEXA):c.1444G>T(p.Glu482Ter) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 34)
• Consequence: HEXA NM_000520.6 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.49

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]

(HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 19 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 15-72345528-C-A is Pathogenic according to our data. Variant chr15-72345528-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 918075.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HEXA	NM_000520.6	c.1444G>T	p.Glu482Ter	stop_gained	13/14	ENST00000268097.10
HEXA	NM_001318825.2	c.1477G>T	p.Glu493Ter	stop_gained	13/14
HEXA	NR_134869.3	n.1229G>T		non_coding_transcript_exon_variant	11/11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HEXA	ENST00000268097.10	c.1444G>T	p.Glu482Ter	stop_gained	13/14	1	NM_000520.6	P1
	ENST00000570175.1	n.308C>A		non_coding_transcript_exon_variant	2/3	1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Tay-Sachs disease Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn

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In exon 13 of the HEXA gene, the heterozygous nonsense variant NM_000520.5:c .1444G>T;p.Glu482Ter was detected which was inherited from the patient's mother; this variant could not be detected in the father. This variant is not listed in the population-based databases. In the phenotype-related database HGMD it is listed as pathogenic (PubMed: 31388111), in the other phenotype-related databases this nonsense variant is not listed. The ACMG classification for this variant is: pathogenic (class 5: PVS1, PM2, PP5) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.66
Cadd	Pathogenic	41
Dann	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	1.0	D
MutationTaster	Benign	1.0	A;A;D;D
Vest4		0.98
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.15		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

Other links and lift over

dbSNP: rs121907952; hg19: chr15-72637869;