Is CTNS p.Asn4= (c.12T>C) pathogenic?

CTNS p.Asn4= (c.12T>C) is classified Likely benign in CTNS (ClinVar, Single submitter, 1 submitter; last evaluated 2025-08-11). Very rare (popmax 0.000763%, nfe); Associated with ocular cystinosis.

What condition is associated with CTNS p.Asn4= (c.12T>C)?

CTNS p.Asn4= (c.12T>C) is associated with ocular cystinosis, juvenile nephropathic cystinosis (ClinVar).

How common is CTNS p.Asn4= (c.12T>C) in the general population?

CTNS p.Asn4= (c.12T>C) is very rare (popmax 0.000763%, nfe) (gnomAD).

How is Cystinosis inherited?

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

CTNS p.Asn4=

c.12T>C · rs550375830 · VCV1078471

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.000763%, nfe)

Conditions

ocular cystinosis

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 -0.8	GERP -0.63, phastCons 0.014
Overall
CADD	7.765	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.000763% European (non-Finnish) · 9/1,179,916 alleles

Filtering AF 0.000359% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00026%

Overall 0.000616% 9/1,461,736 alleles · very rare

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: CTNS
Protein: p.Asn4=
Coding: c.12T>C
MANE Select: NM_004937
dbSNP: rs550375830
Type: single nucleotide variant
Location: chr17:3640218 (GRCh38)
Gene constraint: LOEUF 0.754 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 89.27 · 6 PDB

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

Disease context

ocular cystinosis — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: juvenile nephropathic cystinosis

For Cystinosis (Orphanet):

Inheritance: Autosomal recessive
Onset: Adolescent, Adult, Childhood, Infancy
Prevalence: 1-9 / 1 000 000 (Worldwide)

Similar variants

CTNS c.140+1G>T Pathogenic/Likely pathogenic ★★ same condition
CTNS c.140+2T>C Pathogenic/Likely pathogenic ★★ same condition
CTNS c.141-1G>A Pathogenic/Likely pathogenic ★★ same condition
CTNS c.141-24T>C Pathogenic ★★ same condition
CTNS c.225+3A>T Pathogenic/Likely pathogenic ★★ same condition
CTNS c.225+5G>A Likely pathogenic ★★ same condition
CTNS c.61+2T>C Likely pathogenic ★★ same condition
CTNS c.61+5G>A Pathogenic/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/ctns-p-asn4 (accessed [today's date]).

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