Is SDHB p.Trp218Ser (c.653G>C) pathogenic?

SDHB p.Trp218Ser (c.653G>C) is classified Likely pathogenic in SDHB (ClinVar, Single submitter, 4 submitters; last evaluated 2017-02-09). AlphaMissense: likely pathogenic (0.9946); Absent from gnomAD v4.1; Associated with hereditary neoplastic syndrome.

What condition is associated with SDHB p.Trp218Ser (c.653G>C)?

SDHB p.Trp218Ser (c.653G>C) is associated with hereditary neoplastic syndrome (ClinVar).

How common is SDHB p.Trp218Ser (c.653G>C) in the general population?

SDHB p.Trp218Ser (c.653G>C) is absent from gnomAD v4.1 (gnomAD).

What do computational predictors say about SDHB p.Trp218Ser (c.653G>C)?

AlphaMissense predicts likely pathogenic (score 0.9946) — an in-silico prediction, not a clinical call.

SDHB p.Trp218Ser

c.653G>C · rs1553177290 · VCV480794

Likely pathogenic Single submitter

Classification

Likely pathogenic

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 4 submitters

AlphaMissense

likely pathogenic

0.9946 · ACMG-weighted

gnomAD v4.1

Absent

absent from gnomAD v4.1

Missense predictors

3/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

hereditary neoplastic syndrome

Computational evidence

Protein change
AlphaMissense	0.9946	likely pathogenic ✓ concordant with ClinVar · top 10% in SDHB
REVEL	0.935	strongly pathogenic-leaning
SaProt	LLR -14.94	damaging
⇒ AlphaMissense, REVEL and SaProt all call this damaging.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 7.7	GERP 2.1, phastCons 1
Regional constraint	o/e 0.98	unconstrained · MANE · 35 kb · p 0.67 · regional, not allelic
Overall
CADD	34.0	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: SDHB
Protein: p.Trp218Ser
Coding: c.653G>C
MANE Select: NM_003000
dbSNP: rs1553177290
Type: single nucleotide variant
Location: chr1:17022720 (GRCh38)
Gene constraint: LOEUF 0.741 · pLI 0.03 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 92.14 · 6 PDB
Residue 218: the 'interaction with sdhaf1' region; an α-helix

Full SDHB 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

Similar variants

SDHB p.Trp218Ter Pathogenic ★★ same residue
SDHB p.Trp218Cys Conflicting classifications of pathogenicity ★ ⚠ same residue
SDHB c.200+1G>C Pathogenic/Likely pathogenic ★★ same condition
SDHB c.200+5G>T Likely pathogenic ★★ same condition
SDHB c.201-1G>C Pathogenic/Likely pathogenic ★★ same condition
SDHB c.201-2A>C Pathogenic ★★ same condition
SDHB c.286+1G>A Pathogenic ★★ same condition
SDHB c.286+2T>A 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/sdhb-p-trp218ser (accessed [today's date]).

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