Is FTCD p.Lys218= (c.654A>G) pathogenic?

FTCD p.Lys218= (c.654A>G) is classified Likely benign in FTCD (ClinVar, Single submitter, 1 submitter; last evaluated 2022-10-20). Absent from gnomAD v4.1; Associated with formiminoglutamic aciduria.

What condition is associated with FTCD p.Lys218= (c.654A>G)?

FTCD p.Lys218= (c.654A>G) is associated with formiminoglutamic aciduria (ClinVar).

How common is FTCD p.Lys218= (c.654A>G) in the general population?

FTCD p.Lys218= (c.654A>G) is absent from gnomAD v4.1 (gnomAD).

How is Formiminoglutamic aciduria inherited?

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

FTCD p.Lys218=

c.654A>G · rs2123557644 · VCV2809033

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Absent

absent from gnomAD v4.1

Conditions

formiminoglutamic aciduria

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 1.3	GERP 0.24, phastCons 1
Overall
CADD	7.424	PHRED · no single calibrated threshold — expert panels disagree

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: FTCD
Protein: p.Lys218=
Coding: c.654A>G
MANE Select: NM_206965
dbSNP: rs2123557644
Type: single nucleotide variant
Location: chr21:46150508 (GRCh38)
Gene constraint: LOEUF 1.61 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 95.30
Residue 218: the 'formiminotransferase c-subdomain' region

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

Disease context

formiminoglutamic aciduria — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Formiminoglutamic aciduria (Orphanet):

Inheritance: Autosomal recessive
Onset: Childhood

Similar variants

FTCD p.Arg255Ter Pathogenic ★★ same condition
FTCD p.Arg71Ter Pathogenic/Likely pathogenic ★★ same condition
FTCD p.Leu536Ter Pathogenic/Likely pathogenic ★★ same condition
FTCD p.Ala108Thr Uncertain significance ★★ ⚠ same condition
FTCD p.Ala159Val Uncertain significance ★★ ⚠ same condition
FTCD p.Ala368Val Uncertain significance ★★ ⚠ same condition
FTCD p.Ala418Thr Uncertain significance ★★ ⚠ same condition
FTCD p.Ala455Thr Uncertain significance ★★ ⚠ 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/ftcd-p-lys218 (accessed [today's date]).

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