Is CHIT1 p.Ser240= (c.720C>T) pathogenic?

CHIT1 p.Ser240= (c.720C>T) is classified Likely benign in CHIT1 (ClinVar, Single submitter, 1 submitter; last evaluated 2022-02-19). Ultra-rare (popmax 0.0117%, amr); Associated with Chitotriosidase deficiency.

What condition is associated with CHIT1 p.Ser240= (c.720C>T)?

CHIT1 p.Ser240= (c.720C>T) is associated with Chitotriosidase deficiency (ClinVar).

How common is CHIT1 p.Ser240= (c.720C>T) in the general population?

CHIT1 p.Ser240= (c.720C>T) is ultra-rare (popmax 0.0117%, amr) (gnomAD).

CHIT1 p.Ser240=

c.720C>T · rs769867480 · VCV1956417

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

ultra-rare (popmax 0.0117%, amr)

Conditions

Chitotriosidase deficiency

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 -5.2	GERP -3.4
Overall
CADD	0.257	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0117% Admixed American · 7/60,028 alleles

Filtering AF 0.00543% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0038%

Overall 0.000434% 7/1,614,074 alleles · ultra-rare exomes 7/1,461,748 · genomes 0/152,326 · joint denominator

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: CHIT1
Protein: p.Ser240=
Coding: c.720C>T
MANE Select: NM_003465
dbSNP: rs769867480
Type: single nucleotide variant
Location: chr1:203222211 (GRCh38)
Gene constraint: LOEUF 1.147 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 91.72 · 23 PDB
Residue 240: the gh18 domain; an α-helix

Full CHIT1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

Chitotriosidase deficiency — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Similar variants

CHIT1 c.-13G>A Uncertain significance ★★ same condition
CHIT1 c.*119C>T Uncertain significance ★★ same condition
CHIT1 p.Arg128His Uncertain significance ★★ ⚠ same condition
CHIT1 p.Arg432Trp Uncertain significance ★★ ⚠ same condition
CHIT1 p.Pro451Arg Uncertain significance ★★ ⚠ same condition
CHIT1 c.25+8G>T Likely benign ★★ same condition
CHIT1 c.258-6T>C Benign ★★ same condition
CHIT1 p.Ala442Gly Benign ★★ 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/chit1-p-ser240 (accessed [today's date]).

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