chr5-74720617-G-A

Variant names:

• chr5-74720617-G-A
• rs201580118
• NM_000521.4:c.1509-26G>A

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM2 PP3_Moderate PP5_Very_Strong

The NM_000521.4(HEXB):​c.1509-26G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000381 in 1,602,706 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000041 (0 hom.)
• Consequence: HEXB NM_000521.4 intron
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:12
• Conservation: PhyloP100: -1.46
• Publications: 2 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: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P, ClinGen, Genomics England PanelApp, Myriad Women’s Health

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 5-74720617-G-A is Pathogenic according to our data. Variant chr5-74720617-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 527971.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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HEXB	NM_000521.4	MANE Select	c.1509-26G>A		intron	N/A	NP_000512.2
	HEXB	NM_001292004.2		c.834-26G>A		intron	N/A	NP_001278933.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HEXB	ENST00000261416.12	TSL:1 MANE Select	c.1509-26G>A		intron	N/A	ENSP00000261416.7
	HEXB	ENST00000511181.5	TSL:1	c.834-26G>A		intron	N/A	ENSP00000426285.1
	HEXB	ENST00000513336.5	TSL:3	c.444-26G>A		intron	N/A	ENSP00000423713.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152124 Hom.: 0 Cov.: 32

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: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000478 AC: 12 AN: 250940 AF XY: 0.0000663

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: 0.000106

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000414 AC: 60 AN: 1450582 Hom.: 0 Cov.: 28 AF XY: 0.0000388 AC XY: 28 AN XY: 722404

African (AFR) AF: 0.0000301 AC: 1 AN: 33242

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26060

East Asian (EAS) AF: 0.00 AC: 0 AN: 39648

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86072

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53392

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5744

European-Non Finnish (NFE) AF: 0.0000481 AC: 53 AN: 1101694

Other (OTH) AF: 0.0000833 AC: 5 AN: 60014

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152124 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74288

African (AFR) AF: 0.00 AC: 0 AN: 41424

American (AMR) AF: 0.00 AC: 0 AN: 15262

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3464

East Asian (EAS) AF: 0.00 AC: 0 AN: 5190

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10612

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68022

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000227

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
8	-	-	Sandhoff disease (8)
2	-	-	not provided (2)
1	-	-	Inborn genetic diseases (1)
1	-	-	Sandhoff disease, juvenile form (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.83
CADD	Pathogenic	26
DANN	Benign	0.33
PhyloP100		-1.5
Mutation Taster		=27/73	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
Splicevardb		3.0
SpliceAI score (max)		0.95		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.95		Position offset: 2

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

Other links and lift over

dbSNP: rs201580118; hg19: chr5-74016442;