Is SDHA p.Ser321= (c.963T>C) pathogenic?

SDHA p.Ser321= (c.963T>C) is classified Benign/Likely benign in SDHA (ClinVar, Multiple submitters, 4 submitters; last evaluated 2025-03-04). Very rare (popmax 0.00988%, sas); Associated with hereditary neoplastic syndrome.

What condition is associated with SDHA p.Ser321= (c.963T>C)?

SDHA p.Ser321= (c.963T>C) is associated with hereditary neoplastic syndrome, pheochromocytoma/paraganglioma syndrome 5, mitochondrial complex II deficiency, nuclear type 1 (ClinVar).

How common is SDHA p.Ser321= (c.963T>C) in the general population?

SDHA p.Ser321= (c.963T>C) is very rare (popmax 0.00988%, sas) (gnomAD).

SDHA p.Ser321=

c.963T>C · rs755235011 · VCV1529862

Benign/Likely benign Multiple submitters

Classification

Benign/Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 4 submitters

gnomAD v4.1

Rare

very rare (popmax 0.00988%, sas)

Conditions

hereditary neoplastic syndrome

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 -0.61	GERP -2.8, phastCons 0.048
Overall
CADD	8.245	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00988% South Asian · 9/91,078 alleles

Filtering AF 0.00514% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00375%

Overall 0.000558% 9/1,614,202 alleles · very rare exomes 9/1,461,874 · genomes 0/152,328 · joint denominator

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: SDHA
Protein: p.Ser321=
Coding: c.963T>C
MANE Select: NM_004168
dbSNP: rs755235011
Type: single nucleotide variant
Location: chr5:233544 (GRCh38)
Gene constraint: LOEUF 0.786 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 94.06 · 5 PDB

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

Disease context

hereditary neoplastic syndrome — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: pheochromocytoma/paraganglioma syndrome 5 mitochondrial complex II deficiency, nuclear type 1

Similar variants

SDHA p.Ser321Ile Uncertain significance ★★ ⚠ same residue
SDHA p.Ser321Arg Uncertain significance ★ ⚠ same residue
SDHA c.1064+1G>A Likely pathogenic ★★ same condition
SDHA c.1064+1G>T Likely pathogenic ★★ same condition
SDHA c.1064+2T>A Likely pathogenic ★★ same condition
SDHA c.1065-2A>G Likely pathogenic ★★ same condition
SDHA c.1260+1G>T Likely pathogenic ★★ same condition
SDHA c.1260+2T>A 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/sdha-p-ser321 (accessed [today's date]).

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