NM_000520.6:c.788C>A

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1PM2PM5PP3_Strong

The NM_000520.6(HEXA):c.788C>A(p.Thr263Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,816 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T263I) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

HEXA
NM_000520.6 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 9.88

Publications

0 publications found

Variant links:

Genes affected

HEXA (HGNC:4878): (hexosaminidase subunit alpha) This gene encodes a member of the glycosyl hydrolase 20 family of proteins. The encoded preproprotein is proteolytically processed to generate the alpha subunit of the lysosomal enzyme beta-hexosaminidase. This enzyme, together with the cofactor GM2 activator protein, catalyzes the degradation of the ganglioside GM2, and other molecules containing terminal N-acetyl hexosamines. Mutations in this gene lead to an accumulation of GM2 ganglioside in neurons, the underlying cause of neurodegenerative disorders termed the GM2 gangliosidoses, including Tay-Sachs disease (GM2-gangliosidosis type I). Alternative splicing results in multiple transcript variants, at least one of which encodes a preproprotein that is proteolytically processed. [provided by RefSeq, Jan 2016]

HEXA Gene-Disease associations (from GenCC):

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

HEXA links:

ENSG00000261460 (HGNC:58304):

ENSG00000261460 links:

ENSG00000260729 (HGNC:):

ENSG00000260729 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 ACMG points.

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000520.6

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr15-72350535-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 375356.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.97

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HEXA	NM_000520.6 link	c.788C>A	p.Thr263Asn	missense_variant	Exon 7 of 14	ENST00000268097.10	NP_000511.2	P06865-1A0A0S2Z3W3
HEXA	NM_001318825.2 link	c.821C>A	p.Thr274Asn	missense_variant	Exon 7 of 14		NP_001305754.1	P06865H3BP20B4DVA7
HEXA	NR_134869.3 link	n.830C>A		non_coding_transcript_exon_variant	Exon 7 of 11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HEXA	ENST00000268097.10 link	c.788C>A	p.Thr263Asn	missense_variant	Exon 7 of 14	1	NM_000520.6	ENSP00000268097.6		P06865-1
ENSG00000260729	ENST00000379915.4 link	n.413-4210C>A		intron_variant	Intron 3 of 15	2		ENSP00000478716.1		A0A087WUJ7

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461816

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727206

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5724

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112008

Other (OTH)

AF:

0.00

AC:

AN:

60384

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

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.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.67

BayesDel_addAF

Pathogenic

0.30

BayesDel_noAF

Pathogenic

0.19

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.97

D;.;D

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

1.0

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Pathogenic

0.98

D;D;D

M_CAP

Pathogenic

0.31

MetaRNN

Pathogenic

0.97

D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.5

H;.;.

PhyloP100

9.9

PrimateAI

Uncertain

0.70

PROVEAN

Pathogenic

-4.5

D;D;D

REVEL

Pathogenic

0.85

Sift

Uncertain

0.0010

D;D;D

Sift4G

Uncertain

0.0030

D;D;D

Polyphen

1.0

D;.;.

Vest4

0.93

MutPred

0.83

Gain of catalytic residue at T263 (P = 0.0969);.;Gain of catalytic residue at T263 (P = 0.0969);

MVP

1.0

MPC

0.80

ClinPred

1.0

GERP RS

5.9

Varity_R

0.97

gMVP

0.96

Mutation Taster

=8/92

disease causing

(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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over