Genetic Variant HEXB:c.512-3C>T (chr5-74696690-C-T) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_000521.4(HEXB):c.512-3C>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000161 in 1,238,470 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 predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000016 ( 0 hom. )

Consequence

HEXB
NM_000521.4 splice_region, intron

Scores

Splicing: ADA: 0.0009230

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -0.844

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: Labcorp Genetics (formerly Invitae), Ambry Genetics, Genomics England PanelApp, Myriad Women’s Health, G2P, ClinGen

HEXB links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.67).

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.512-3C>T		splice_region intron	N/A	NP_000512.2	P07686
	HEXB	NM_001292004.2		c.-164-3C>T		splice_region intron	N/A	NP_001278933.1	Q5URX0

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
HEXB	ENST00000261416.12	TSL:1 MANE Select	c.512-3C>T	splice_region intron	N/A	ENSP00000261416.7	P07686
HEXB	ENST00000511181.5	TSL:1	c.-164-3C>T	splice_region intron	N/A	ENSP00000426285.1	Q5URX0
HEXB	ENST00000510820.1	TSL:3	n.231-3C>T	splice_region intron	N/A

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000161

AC:

AN:

1238470

Hom.:

Cov.:

AF XY:

0.00000159

AC XY:

AN XY:

627184

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

29006

American (AMR)

AF:

0.00

AC:

AN:

44108

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

24602

East Asian (EAS)

AF:

0.00

AC:

AN:

38368

South Asian (SAS)

AF:

0.00

AC:

AN:

80914

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53070

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5320

European-Non Finnish (NFE)

AF:

0.00000220

AC:

AN:

910334

Other (OTH)

AF:

0.00

AC:

AN:

52748

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

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

Cov.:

Alfa

AF:

0.0000312

Hom.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.67

CADD

Benign

6.4

(source)

DANN

Benign

0.58

PhyloP100

-0.84

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.00092

dbscSNV1_RF

Benign

0.070

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over