Is HEXA p.Ser265= (c.795C>T) pathogenic?

HEXA p.Ser265= (c.795C>T) is classified Likely benign in HEXA (ClinVar, Single submitter, 1 submitter; last evaluated 2023-12-14). Very rare (popmax 0.00669%, eas); Associated with Tay-Sachs disease.

What condition is associated with HEXA p.Ser265= (c.795C>T)?

HEXA p.Ser265= (c.795C>T) is associated with Tay-Sachs disease (ClinVar).

How common is HEXA p.Ser265= (c.795C>T) in the general population?

HEXA p.Ser265= (c.795C>T) is very rare (popmax 0.00669%, eas) (gnomAD).

How is Tay-Sachs disease inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

HEXA p.Ser265=

c.795C>T · rs746942625 · VCV792633

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00669%, eas)

Conditions

Tay-Sachs disease

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 1.1	GERP -1.4, phastCons 1
Overall
CADD	12.26	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00669% East Asian · 3/44,876 alleles

Filtering AF 0.00177% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000891%

Overall 0.000274% 4/1,461,780 alleles · very rare

Ancestry group	Frequency	1 in
East Asiangrpmax	0.00669%	14,959
Remaining individualsnot grpmax-eligible	0.0016%	62,494

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: HEXA
Protein: p.Ser265=
Coding: c.795C>T
MANE Select: NM_000520
dbSNP: rs746942625
Type: single nucleotide variant
Location: chr15:72350528 (GRCh38)
Gene constraint: LOEUF 0.947 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 93.62 · 2 PDB
Residue 265: a turn

Full HEXA gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Tay-Sachs disease — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Tay-Sachs disease (Orphanet):

Inheritance: Autosomal recessive
Onset: All ages
Prevalence: 1-5 / 10 000 (Specific population)

Similar variants

HEXA c.1073+1G>A Pathogenic/Likely pathogenic ★★ same condition
HEXA c.1330+1G>A Pathogenic ★★ same condition
HEXA c.1330+2T>C Pathogenic ★★ same condition
HEXA c.1421+1G>C Pathogenic ★★ same condition
HEXA c.1421+1G>T Pathogenic/Likely pathogenic ★★ same condition
HEXA c.1526+1G>T Pathogenic/Likely pathogenic ★★ same condition
HEXA c.253+1G>A Likely pathogenic ★★ same condition
HEXA c.254-1G>C Likely pathogenic ★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/hexa-p-ser265 (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown