Is CTNS p.Ser85Cys (c.254C>G) pathogenic?

CTNS p.Ser85Cys (c.254C>G) is classified Uncertain significance in CTNS (ClinVar, Single submitter, 1 submitter; last evaluated 2024-04-29). AlphaMissense: likely benign (0.1024); Very rare (popmax 0.000424%, nfe); Associated with juvenile nephropathic cystinosis.

What condition is associated with CTNS p.Ser85Cys (c.254C>G)?

CTNS p.Ser85Cys (c.254C>G) is associated with juvenile nephropathic cystinosis, ocular cystinosis, nephropathic cystinosis (ClinVar).

How common is CTNS p.Ser85Cys (c.254C>G) in the general population?

CTNS p.Ser85Cys (c.254C>G) is very rare (popmax 0.000424%, nfe) (gnomAD).

What do computational predictors say about CTNS p.Ser85Cys (c.254C>G)?

AlphaMissense predicts likely benign (score 0.1024) — an in-silico prediction, not a clinical call.

CTNS p.Ser85Cys

c.254C>G · VCV3581864

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.1024 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.000424%, nfe)

Missense predictors

0/2 damaging

AlphaMissense, SaProt · REVEL no call

Conditions

juvenile nephropathic cystinosis

Computational evidence

Protein change
AlphaMissense	0.1024	likely benign
REVEL	0.33	indeterminate
SaProt	LLR -9.67	tolerated
⇒ AlphaMissense and SaProt both call this tolerated; REVEL makes no call.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 1.7	GERP 1.9, phastCons 0.029
Regional constraint	o/e 0.96	unconstrained · MANE · 20 kb · p 0.4 · regional, not allelic
Overall
CADD	18.77	PHRED · no single calibrated threshold — expert panels disagree

ClinVar classifies this uncertain; the computational predictors unanimously lean tolerated — a triage signal, not a reclassification

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

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.000424% European (non-Finnish) · 5/1,179,868 alleles

Filtering AF 0.000124% ClinGen BA1/BS1 input FAF95, joint · FAF99 9e-05%

Overall 0.00031% 5/1,613,880 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.Ser85Cys
Coding: c.254C>G
MANE Select: NM_004937
Type: single nucleotide variant
Location: chr17:3655026 (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

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

Also linked: ocular cystinosis nephropathic cystinosis

Similar variants

CTNS p.Ser85Thr Uncertain significance ★ ⚠ same residue
CTNS c.140+1G>C Likely pathogenic ★★ same condition
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

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-ser85cys (accessed [today's date]).

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