rs1309123671

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2PP3PP5_Very_Strong

The NM_000521.4(HEXB):c.1242G>A(p.Lys414Lys) variant causes a splice region, synonymous change. The variant allele was found at a frequency of 0.00000187 in 1,601,510 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

HEXB
NM_000521.4 splice_region, synonymous

Scores

Splicing: ADA: 0.9988

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 5.48

Variant links:

Genes affected

HEXB (HGNC:4879): (hexosaminidase subunit beta) Hexosaminidase B is the beta subunit of the lysosomal enzyme beta-hexosaminidase that, together with the cofactor GM2 activator protein, catalyzes the degradation of the ganglioside GM2, and other molecules containing terminal N-acetyl hexosamines. Beta-hexosaminidase is composed of two subunits, alpha and beta, which are encoded by separate genes. Both beta-hexosaminidase alpha and beta subunits are members of family 20 of glycosyl hydrolases. Mutations in the alpha or beta subunit genes lead to an accumulation of GM2 ganglioside in neurons and neurodegenerative disorders termed the GM2 gangliosidoses. Beta subunit gene mutations lead to Sandhoff disease (GM2-gangliosidosis type II). Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2014]

HEXB 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;

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

PP5

Variant 5-74718363-G-A is Pathogenic according to our data. Variant chr5-74718363-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 558077.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
HEXB	NM_000521.4 link	c.1242G>A	p.Lys414Lys	splice_region_variant, synonymous_variant	Exon 10 of 14	ENST00000261416.12	NP_000512.2	P07686A0A024RAJ6
HEXB	NM_001292004.2 link	c.567G>A	p.Lys189Lys	splice_region_variant, synonymous_variant	Exon 10 of 14		NP_001278933.1	P07686Q5URX0

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HEXB	ENST00000261416.12 link	c.1242G>A	p.Lys414Lys	splice_region_variant, synonymous_variant	Exon 10 of 14	1	NM_000521.4	ENSP00000261416.7		P07686

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152160

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251298

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135828

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000138

AC:

AN:

1449350

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

721818

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000182

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152160

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74338

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000508

Hom.:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Sandhoff disease

Pathogenic:4

Apr 19, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: HEXB c.1242G>A (p.Lys414Lys) located at the last nucleotide of the exon alters a conserved nucleotide located adjacent to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Several computational tools predict a significant impact on normal splicing: Three predict the variant weakens the canonical 5' donor site. One predict the variant abolishes the canonical 5' splicing donor site. At least one publication reports experimental evidence that this variant affects mRNA splicing resulting in exon 10 skipping (example, Gomez-Lira_1998). The variant allele was found at a frequency of 4e-06 in 251298 control chromosomes. c.1242G>A has been reported in the literature as a homozygous and compound heterozygous genotype in at-least two individuals affected with Sandhoff Disease (example, Gomez-Lira_1998, Sobek_2012). These data indicate that the variant may be associated with disease. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

May 01, 2018

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 22, 2024

3billion

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: <0.001%). Predicted Consequence/Location: Synonymous variant In silico tools predict the variant to alter splicing and produce an abnormal transcript [SpliceAI: 0.60 (>=0.2, moderate evidence for spliceogenicity)]. The variant has been reported at least twice as pathogenic with clinical assertions and evidence for the classification (ClinVar ID: VCV000558077 /PMID: 9475608). Therefore, this variant is classified as Likely pathogenic according to the recommendation of ACMG/AMP guideline. -

Mar 07, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects codon 414 of the HEXB mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the HEXB protein. RNA analysis indicates that this variant induces altered splicing and may result in an absent or disrupted protein product. This variant is present in population databases (no rsID available, gnomAD 0.004%). This variant has been observed in individual(s) with Sandhoff disease (PMID: 9475608, 23010210). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 558077). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant results in skipping of exon 10 and introduces a premature termination codon (PMID: 9475608). The resulting mRNA is expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.24

CADD

Benign

DANN

Benign

0.91

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.8

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.98

SpliceAI score (max)

0.52

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.52

Position offset: 0

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