Is FTCD p.Cys107= (c.321C>T) pathogenic?

FTCD p.Cys107= (c.321C>T) is classified Likely benign in FTCD (ClinVar, Single submitter, 1 submitter; last evaluated 2021-03-08). Ultra-rare (popmax 0.0243%, nfe); Associated with formiminoglutamic aciduria.

What condition is associated with FTCD p.Cys107= (c.321C>T)?

FTCD p.Cys107= (c.321C>T) is associated with formiminoglutamic aciduria (ClinVar).

How common is FTCD p.Cys107= (c.321C>T) in the general population?

FTCD p.Cys107= (c.321C>T) is ultra-rare (popmax 0.0243%, nfe) (gnomAD).

How is Formiminoglutamic aciduria inherited?

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

FTCD p.Cys107=

c.321C>T · rs373447719 · VCV1530469

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

ultra-rare (popmax 0.0243%, nfe)

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 -0.16	GERP -2.7, phastCons 0.005
Overall
CADD	8.455	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0243% European (non-Finnish) · 280/1,153,786 alleles

Filtering AF 0.0219% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0209%

Overall 0.0191% 299/1,562,732 alleles · ultra-rare exomes 286/1,410,382 · genomes 13/152,350 · joint denominator

Ancestry group	Frequency	1 in
European (non-Finnish)grpmax	0.0243%	4,121
Remaining individualsnot grpmax-eligible	0.0115%	8,659
East Asian	0.00706%	14,163
South Asian	0.00471%	21,253
African / African-American	0.00405%	24,713
Finnishnot grpmax-eligible	0.0034%	29,384

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: FTCD
Protein: p.Cys107=
Coding: c.321C>T
MANE Select: NM_206965
dbSNP: rs373447719
Type: single nucleotide variant
Location: chr21:46152953 (GRCh38)
Gene constraint: LOEUF 1.61 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 95.30
Residue 107: the 'formiminotransferase n-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.Cys107Arg Conflicting classifications of pathogenicity ★ ⚠ same residue
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

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-cys107 (accessed [today's date]).

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