rs763517499

Variant names:

• chr5-74718976-G-A
• rs763517499
• NM_000521.4:c.1417+5G>A

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM2 PP3 PP5_Very_Strong

The NM_000521.4(HEXB):​c.1417+5G>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,461,692 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: HEXB NM_000521.4 splice_region, intron
• Scores: Splicing: ADA: 0.9955
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 U:1
• Conservation: PhyloP100: 2.06
• Publications: 3 publications found

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 Gene-Disease associations (from GenCC):

• Sandhoff disease

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Myriad Women’s Health, ClinGen, Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, max_spliceai. No scorers claiming Uncertain. Scorers claiming Benign: dbscSNV1_RF.
• PP5: Variant 5-74718976-G-A is Pathogenic according to our data. Variant chr5-74718976-G-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 557105.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000521.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HEXB	NM_000521.4	MANE Select	c.1417+5G>A		splice_region intron	N/A	NP_000512.2	P07686
	HEXB	NM_001292004.2		c.742+5G>A		splice_region intron	N/A	NP_001278933.1	Q5URX0

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HEXB	ENST00000261416.12	TSL:1 MANE Select	c.1417+5G>A		splice_region intron	N/A	ENSP00000261416.7	P07686
	HEXB	ENST00000511181.5	TSL:1	c.742+5G>A		splice_region intron	N/A	ENSP00000426285.1	Q5URX0
	HEXB	ENST00000513336.5	TSL:3	c.352+5G>A		splice_region intron	N/A	ENSP00000423713.1	H0Y9B6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000159 AC: 4 AN: 251454 AF XY: 0.0000221

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: 0.0000264

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000684 AC: 10 AN: 1461692 Hom.: 0 Cov.: 32 AF XY: 0.0000124 AC XY: 9 AN XY: 727160

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.0000580 AC: 5 AN: 86250

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000450 AC: 5 AN: 1111848

Other (OTH) AF: 0.00 AC: 0 AN: 60390

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
1	1	-	Sandhoff disease (2)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.37
CADD	Benign	23
DANN	Benign	0.80
PhyloP100		2.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Benign	0.69
SpliceAI score (max)		0.85		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.53		Position offset: 44
DS_DL_spliceai		0.85		Position offset: -5

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

Other links and lift over

dbSNP: rs763517499; hg19: chr5-74014801;