Genetic Variant NM_000520.6:c.1444G>A (chr15-72345528-C-T) – ACMG Classification: Pathogenic (20 pts)

Variant summary

Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PS3PM1PM2PP3_StrongPP5_Very_Strong

The NM_000520.6(HEXA):c.1444G>A(p.Glu482Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000743 in 1,614,102 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV002170069: Experimental studies have shown that this missense change affects HEXA function (PMID:1301190, 8328462, 27682588)." and additional evidence is available in ClinVar.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 34)

Exomes 𝑓: 0.0000075 ( 0 hom. )

Consequence

HEXA
NM_000520.6 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 7.49

Publications

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

HEXA links:

ENSG00000260729 (HGNC:):

ENSG00000260729 links:

CELF6-AS1 (HGNC:58304):

CELF6-AS1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 20 ACMG points.

PS3

PS3 evidence extracted from ClinVar submissions: SCV002170069: Experimental studies have shown that this missense change affects HEXA function (PMID: 1301190, 8328462, 27682588).; SCV002767346: Studies on patient fibroblasts demonstrated markedly reduced enzymatic activities and in vitro analysis demonstrated this is due to altered folding and inability to be secreted (PMID: 27682588).; SCV003934606: "At least one publication reports experimental evidence evaluating an impact on protein function (Dersh_2019). The most pronounced variant effect results in abolishment of enzymatic activity against MUGS substrate, unprocessed by lysosomal proteases and altered folding as compared to the wild-type enzyme. This study also demonstrated that this variant retrotranslocated from the endoplasmic reticulum (ER) to the cytosol and was degraded by the proteasome, indicating clearance via ER-associated degradation (ERAD)." PMID: 27682588; SCV003571847: Enzymatic activity was undetectable in both cultured patient fibroblasts and cells transiently expressing p.E482K. In addition, p.E482K was severely misfolded and degraded by the proteosome (Brown, 1993; Dersh, 2016).

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 13 uncertain in NM_000520.6

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.991

PP5

Variant 15-72345528-C-T is Pathogenic according to our data. Variant chr15-72345528-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 3892.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000520.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
HEXA	NM_000520.6	MANE Select	c.1444G>A	p.Glu482Lys	missense	Exon 13 of 14	NP_000511.2	P06865-1
HEXA	NM_001318825.2		c.1477G>A	p.Glu493Lys	missense	Exon 13 of 14	NP_001305754.1	H3BP20
HEXA	NR_134869.3		n.1229G>A		non_coding_transcript_exon	Exon 11 of 11

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
HEXA	ENST00000268097.10	TSL:1 MANE Select	c.1444G>A	p.Glu482Lys	missense	Exon 13 of 14	ENSP00000268097.6	P06865-1
HEXA	ENST00000567159.5	TSL:1	c.1444G>A	p.Glu482Lys	missense	Exon 13 of 13	ENSP00000456489.1	H3BS10
ENSG00000260729	ENST00000379915.4	TSL:2	n.526G>A		non_coding_transcript_exon	Exon 5 of 16	ENSP00000478716.1	A0A087WUJ7

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152240

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000795

AC:

AN:

251424

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000752

AC:

AN:

1461862

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727228

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53406

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000719

AC:

AN:

1112004

Other (OTH)

AF:

0.0000166

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.530

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:

152240

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74374

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41462

American (AMR)

AF:

0.00

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68048

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.000138

Hom.:

Bravo

AF:

0.0000264

ClinVar

ClinVar submissions

Significance:Pathogenic/Likely pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Tay-Sachs disease (5)

Inborn genetic diseases (1)

not provided (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.96

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.60

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.98

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

1.0

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Pathogenic

1.0

M_CAP

Pathogenic

0.41

MetaRNN

Pathogenic

0.99

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

4.5

PhyloP100

7.5

PrimateAI

Uncertain

0.60

PROVEAN

Uncertain

-3.7

REVEL

Pathogenic

0.95

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.99

MutPred

0.98

Gain of MoRF binding (P = 0.0081)

MVP

1.0

MPC

0.79

ClinPred

1.0

GERP RS

5.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.99

gMVP

1.0

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.060

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