dbSNP rs768438206: HEXB:p.Ile322LysfsTer5 (chr5-74715572-AT-A) – ACMG Classification: Pathogenic (12 pts)

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_000521.4(HEXB):c.965delT(p.Ile322LysfsTer5) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,612,362 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

Frequency

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

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

HEXB
NM_000521.4 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, single submitter P:3

Conservation

PhyloP100: 8.01

Publications

1 publications found

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 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

HEXB links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 5-74715572-AT-A is Pathogenic according to our data. Variant chr5-74715572-AT-A is described in ClinVar as Pathogenic. ClinVar VariationId is 557437.Status of the report is criteria_provided_single_submitter, 1 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.965delT	p.Ile322LysfsTer5	frameshift	Exon 8 of 14	NP_000512.2	P07686
	HEXB	NM_001292004.2		c.290delT	p.Ile97LysfsTer5	frameshift	Exon 8 of 14	NP_001278933.1	Q5URX0

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
HEXB	ENST00000261416.12	TSL:1 MANE Select	c.965delT	p.Ile322LysfsTer5	frameshift	Exon 8 of 14	ENSP00000261416.7	P07686
HEXB	ENST00000511181.5	TSL:1	c.290delT	p.Ile97LysfsTer5	frameshift	Exon 8 of 14	ENSP00000426285.1	Q5URX0
HEXB	ENST00000504459.5	TSL:3	n.162delT		non_coding_transcript_exon	Exon 2 of 7

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152192

Hom.:

Cov.:

show subpopulations

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:

0.00000398

AC:

AN:

251424

AF XY:

0.00

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.85e-7

AC:

AN:

1460170

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726556

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33454

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.00

AC:

AN:

39670

South Asian (SAS)

AF:

0.00

AC:

AN:

86222

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

9.01e-7

AC:

AN:

1110468

Other (OTH)

AF:

0.00

AC:

AN:

60324

⚠️ 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.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.275

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152192

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74350

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41432

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.625

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

ClinVar

ClinVar submissions

Significance:Pathogenic

Revision:criteria provided, single submitter

View on ClinVar

Pathogenic

VUS

Benign

Condition

Sandhoff disease (2)

Sandhoff disease, infantile form (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

PhyloP100

8.0

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

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

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over