Is CTC1 p.Arg445Cys (c.1333C>T) pathogenic?

CTC1 p.Arg445Cys (c.1333C>T) is classified Conflicting classifications of pathogenicity in CTC1 (ClinVar, Conflicting submitters, 2 submitters; last evaluated 2025-12-13). AlphaMissense: likely benign (0.0793); Ultra-rare (popmax 0.0614%, afr); Associated with dyskeratosis congenita.

What condition is associated with CTC1 p.Arg445Cys (c.1333C>T)?

CTC1 p.Arg445Cys (c.1333C>T) is associated with dyskeratosis congenita (ClinVar).

How common is CTC1 p.Arg445Cys (c.1333C>T) in the general population?

CTC1 p.Arg445Cys (c.1333C>T) is ultra-rare (popmax 0.0614%, afr) (gnomAD).

How is Dyskeratosis congenita inherited?

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

What do computational predictors say about CTC1 p.Arg445Cys (c.1333C>T)?

AlphaMissense predicts likely benign (score 0.0793) — an in-silico prediction, not a clinical call.

CTC1 p.Arg445Cys

c.1333C>T · rs201273283 · VCV855641

Conflicting classifications of pathogenicity Conflicting submitters

Classification

Conflicting classifications of pathogenicity

ClinVar

Review

Conflicting submitters ★☆☆☆

ClinVar · 2 submitters

AlphaMissense

likely benign

0.0793 · ACMG-weighted

gnomAD v4.1

Rare

ultra-rare (popmax 0.0614%, afr)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

dyskeratosis congenita

Computational evidence

Protein change
AlphaMissense	0.0793	likely benign
REVEL	0.194	benign-leaning
SaProt	LLR -7.38	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 2.5	GERP 0.56, phastCons 0.51
Regional constraint	o/e 0.96	unconstrained · MANE · 20 kb · p 0.088 · regional, not allelic
Overall
CADD	18.11	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

Grpmax group 0.0614% African / African-American · 46/74,936 alleles

Filtering AF 0.0472% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0423%

Overall 0.00458% 74/1,614,054 alleles · ultra-rare

Ancestry group	Frequency	1 in
African / African-Americangrpmax	0.0614%	1,629
East Asian	0.0111%	8,981
South Asian	0.00329%	30,363
European (non-Finnish)	0.00161%	62,108
Remaining individualsnot grpmax-eligible	0.0016%	62,490

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: CTC1
Protein: p.Arg445Cys
Coding: c.1333C>T
MANE Select: NM_025099
dbSNP: rs201273283
Type: single nucleotide variant
Location: chr17:8235159 (GRCh38)
Gene constraint: LOEUF 0.776 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 78.01 · 7 PDB
Residue 445: a β-strand

Full CTC1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

dyskeratosis congenita — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Dyskeratosis congenita (Orphanet):

Inheritance: Autosomal dominant, Autosomal recessive, X-linked recessive
Onset: Adolescent, Adult, Childhood, Infancy, Neonatal
Prevalence: 1-9 / 1 000 000 (Europe)

Similar variants

CTC1 p.Arg445His Uncertain significance ★★ ⚠ same residue
CTC1 c.1617+5G>T Pathogenic/Likely pathogenic ★★ same condition
CTC1 c.1818+1G>A Likely pathogenic ★★ same condition
CTC1 c.2386-1G>A Likely pathogenic ★★ same condition
CTC1 c.2758+1G>T Pathogenic/Likely pathogenic ★★ same condition
CTC1 c.3221+1G>A Likely pathogenic ★★ same condition
CTC1 p.Ala227Val Pathogenic ★★ ⚠ same condition
CTC1 p.Arg108Ter 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/ctc1-p-arg445cys (accessed [today's date]).

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