15-72351224-G-C

Variant names:

• chr15-72351224-G-C
• rs778947516
• NM_000520.6:c.581C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000520.6(HEXA):​c.581C>G​(p.Ala194Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000688 in 1,453,290 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. A194V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: HEXA NM_000520.6 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.88
• Publications: 1 publications found

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

ENSG00000261460 (HGNC:58304):

ENSG00000260729 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_000520.6
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.946

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HEXA	NM_000520.6	MANE Select	c.581C>G	p.Ala194Gly	missense	Exon 6 of 14	NP_000511.2
	HEXA	NM_001318825.2		c.614C>G	p.Ala205Gly	missense	Exon 6 of 14	NP_001305754.1
	HEXA	NR_134869.3		n.623C>G		non_coding_transcript_exon	Exon 6 of 11

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HEXA	ENST00000268097.10	TSL:1 MANE Select	c.581C>G	p.Ala194Gly	missense	Exon 6 of 14	ENSP00000268097.6
	HEXA	ENST00000567159.5	TSL:1	c.581C>G	p.Ala194Gly	missense	Exon 6 of 13	ENSP00000456489.1
	ENSG00000261460	ENST00000570175.1	TSL:1	n.2578G>C		non_coding_transcript_exon	Exon 3 of 3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251458 AF XY: 0.00000736

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.88e-7 AC: 1 AN: 1453290 Hom.: 0 Cov.: 28 AF XY: 0.00000138 AC XY: 1 AN XY: 723582

African (AFR) AF: 0.00 AC: 0 AN: 33312

American (AMR) AF: 0.00 AC: 0 AN: 44706

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26084

East Asian (EAS) AF: 0.00 AC: 0 AN: 39646

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86082

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5752

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1104198

Other (OTH) AF: 0.00 AC: 0 AN: 60092

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.28
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.92	D
M_CAP	Uncertain	0.13	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.3	M
PhyloP100		9.9
PrimateAI	Uncertain	0.58	T
PROVEAN	Uncertain	-3.7	D
REVEL	Pathogenic	0.80
Sift	Uncertain	0.0070	D
Sift4G	Uncertain	0.014	D
Polyphen		0.99	D
Vest4		0.74
MutPred		0.86		Loss of catalytic residue at A194 (P = 0.0866)
MVP		1.0
MPC		0.73
ClinPred		0.96	D
GERP RS		5.8
Varity_R		0.82
gMVP		0.79
Mutation Taster		=16/84	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs778947516; hg19: chr15-72643565;