Is CTLA4 p.Thr198= (c.594A>G) pathogenic?

CTLA4 p.Thr198= (c.594A>G) is classified Likely benign in CTLA4 (ClinVar, Single submitter, 1 submitter; last evaluated 2024-07-01). Very rare (popmax 0.00223%, eas); Associated with autoimmune lymphoproliferative syndrome due to CTLA4 haploinsufficiency.

What condition is associated with CTLA4 p.Thr198= (c.594A>G)?

CTLA4 p.Thr198= (c.594A>G) is associated with autoimmune lymphoproliferative syndrome due to CTLA4 haploinsufficiency (ClinVar).

How common is CTLA4 p.Thr198= (c.594A>G) in the general population?

CTLA4 p.Thr198= (c.594A>G) is very rare (popmax 0.00223%, eas) (gnomAD).

CTLA4 p.Thr198=

Q: How is Autoimmune lymphoproliferative syndrome due to CTLA4 haploinsuffiency inherited?

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

c.594A>G · VCV3617125

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00223%, eas)

Conditions

autoimmune lymphoproliferative syndrome due to CTLA4 haploinsufficiency

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
REVEL	0.197	benign-leaning
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 4.1	GERP 0.9, phastCons 1
Overall
CADD	8.79	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00223% East Asian · 1/44,860 alleles

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

Overall 0.000479% 7/1,460,268 alleles · very rare

Ancestry group	Frequency	1 in
East Asiangrpmax	0.00223%	44,860
Admixed American	0.00167%	60,018
European (non-Finnish)	0.000424%	235,718

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: CTLA4
Protein: p.Thr198=
Coding: c.594A>G
MANE Select: NM_005214
Type: single nucleotide variant
Location: chr2:203872734 (GRCh38)
Gene constraint: LOEUF 0.211 · pLI 1.00 (gnomAD)
Structure: AlphaFold pLDDT 79.67 · 22 PDB

Full CTLA4 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

autoimmune lymphoproliferative syndrome due to CTLA4 haploinsufficiency — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Autoimmune lymphoproliferative syndrome due to CTLA4 haploinsuffiency (Orphanet):

Inheritance: Autosomal dominant
Onset: Adolescent, Adult, Childhood

Similar variants

CTLA4 p.Arg51Ter Pathogenic ★★★ same condition
CTLA4 p.Arg75Trp Pathogenic ★★★ ⚠ same condition
CTLA4 p.Asp153Asn Pathogenic ★★★ ⚠ same condition
CTLA4 p.Cys35Ter Pathogenic ★★★ same condition
CTLA4 p.Pro136Ala Likely pathogenic ★★★ same condition
CTLA4 p.Pro136Leu Likely pathogenic ★★★ same condition
CTLA4 p.Pro136Ser Likely pathogenic ★★★ same condition
CTLA4 p.Pro137Arg 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/ctla4-p-thr198 (accessed [today's date]).

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