CTLA4

Chr 2AD

cytotoxic T-lymphocyte associated protein 4

Also known as: ALPS5, CD, CD152, CELIAC3, CTLA-4, GRD4, GSE, IDDM12

This gene is a member of the immunoglobulin superfamily and encodes a protein which transmits an inhibitory signal to T cells. The protein contains a V domain, a transmembrane domain, and a cytoplasmic tail. Alternate transcriptional splice variants, encoding different isoforms, have been characterized. The membrane-bound isoform functions as a homodimer interconnected by a disulfide bond, while the soluble isoform functions as a monomer. Mutations in this gene have been associated with insulin-dependent diabetes mellitus, Graves disease, Hashimoto thyroiditis, celiac disease, systemic lupus erythematosus, thyroid-associated orbitopathy, and other autoimmune diseases. [provided by RefSeq, Jul 2008]

Primary Disease Associations & Inheritance

Immune dysregulation with autoimmunity, immunodeficiency, and lymphoproliferationMIM #616100
AD
UniProtSystemic lupus erythematosus
UniProtType 1 diabetes mellitus 12
UniProtCeliac disease 3
338
ClinVar variants
96
Pathogenic / LP
0.94
pLI score· haploinsufficient
12
Active trials
Clinical SummaryCTLA4
🧬
Gene-Disease Validity (ClinGen)
autoimmune lymphoproliferative syndrome due to CTLA4 haploinsufficiency · ADDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Highly constrained gene — heterozygous loss-of-function variants are very rare in the population (pLI 0.94). One damaged copy is likely sufficient to cause disease.
📋
ClinVar Variants
96 Pathogenic / Likely Pathogenic· 144 VUS of 338 total submissions
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Clinical Trials
12 active or recruiting trials — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

LoF intolerant — likely haploinsufficient
LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.
0.33LOEUF
pLI 0.941
Z-score 2.77
OE 0.00 (0.000.33)
Highly constrained

Highly LoF-intolerant (top ~10% of genes)

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.
1.69Z-score
OE missense 0.58 (0.480.70)
74 obs / 127.6 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.
LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.00 (0.000.33)
00.351.4
Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.58 (0.480.70)
00.61.4
Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.0.88
01.21.6
LoF obs/exp: 0 / 9.0Missense obs/exp: 74 / 127.6Syn Z: 0.65

ClinVar Variant Classifications

338 submitted variants in ClinVar

Classification Summary

Pathogenic72
Likely Pathogenic24
VUS144
Likely Benign67
Benign21
Conflicting10
72
Pathogenic
24
Likely Pathogenic
144
VUS
67
Likely Benign
21
Benign
10
Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
19
6
47
0
72
Likely Pathogenic
5
14
5
0
24
VUS
3
120
17
4
144
Likely Benign
0
8
15
44
67
Benign
0
10
9
2
21
Conflicting
10
Total271589350338

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

CTLA4 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

OMIM — Genotype-Phenotype Relationships

1 OMIM entry

Immune dysregulation with autoimmunity, immunodeficiency, and lymphoproliferation

MIM #616100

Molecular basis of disorder known

Autosomal dominant
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GeneReview available — CTLA4
Authoritative clinical overview · NCBI Bookshelf · Recommended first read
Open GeneReview ↗
Clinical Literature
Landmark / reviewRecent case evidence

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

PI3KCDCTLA4STAT3GOF

Novel Genetic Disorders of the Immune System

RECRUITING
NCT02257892National Institute of Allergy and Infectious Diseases (NIAID)Started 2014-10-22
Non Small Cell Lung CancerImmunotherapyRadiotherapy

A Phase 2 Randomized, Controlled Trial of QL1706 Plus Chemotherapy and Quad Shot for Driver Gene-negative Advanced Non-small Cell Lung Cancer.

NOT YET RECRUITING
NCT07271602Phase PHASE2Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyStarted 2026-01-30
Quad shotChemotherapyImmune Checkpoint Inhibitors
Acinar Cell CarcinomaAdenoid Cystic CarcinomaAdrenal Cortical Carcinoma

Nivolumab and Ipilimumab in Treating Patients With Rare Tumors

ACTIVE NOT RECRUITING
NCT02834013Phase PHASE2National Cancer Institute (NCI)Started 2017-01-30
Biospecimen CollectionComputed TomographyEchocardiography Test
Hepatocellular CarcinomaImmunotherapyCAR

GPC3-CAR-T Cells for Immunotherapy of Cancer With GPC3 Expression

RECRUITING
NCT03198546Phase PHASE1Second Affiliated Hospital of Guangzhou Medical UniversityStarted 2017-07-01
GPC3 and/or TGFβ targeting CAR-T cells
Pancreatic Cancer MetastaticPancreatic Adenocarcinoma Metastatic

The Seven Trial: Exploiting the Unfolded Protein Response

ACTIVE NOT RECRUITING
NCT06076837Phase PHASE1HonorHealth Research InstituteStarted 2025-01-09
BotensilimabBalstilimabChloroquine Phosphate
Clinical Stage III Cutaneous Melanoma AJCC v8Clinical Stage IV Cutaneous Melanoma AJCC v8Metastatic Cutaneous Melanoma

Physician/Patient Choice of Either High-Dose Recombinant Interferon Alfa-2B or Ipilimumab, Versus Pembrolizumab in Treating Patients With Stage III-IV High Risk Melanoma That Has Been Removed by Surgery

ACTIVE NOT RECRUITING
NCT02506153Phase PHASE3National Cancer Institute (NCI)Started 2015-11-10
Biospecimen CollectionComputed TomographyIpilimumab
Anatomic Stage III Breast Cancer AJCC v8Anatomic Stage IV Breast Cancer AJCC v8Breast Adenocarcinoma

Entinostat, Nivolumab, and Ipilimumab in Treating Patients With Solid Tumors That Are Metastatic or Cannot Be Removed by Surgery or Locally Advanced or Metastatic HER2-Negative Breast Cancer

ACTIVE NOT RECRUITING
NCT02453620Phase PHASE1National Cancer Institute (NCI)Started 2016-02-12
Biopsy ProcedureBlood SampleBone Scan
NSCLC (Advanced Non-small Cell Lung Cancer)

QL1706 Combined With Chemotherapy in the Treatment of Immune-mediated NSCLC

RECRUITING
NCT07330596Phase PHASE2Anhui Provincial Cancer HospitalStarted 2025-10-30
QL1706 combined with ChemotherapyChemotherapy
Ovary Cancer

RC48 in Combination With AK104 and Bevacizumab in OCCC

RECRUITING
NCT06540729Phase PHASE2Sun Yat-Sen Memorial Hospital of Sun Yat-Sen UniversityStarted 2024-09-24
Disitamab vedotin in combination with AK104 and bevacizumab for the treatment of recurrent and persistent clear cell ovarian cancer
Breast Cancer MetastaticBreast Carcinoma

Immun Checkpoint Washout in Patients With Invasive Ductal Breast Cancer

RECRUITING
NCT07003009Phase NAIstanbul Training and Research HospitalStarted 2024-01-01
Malign Lymph Node WashoutBenign Lymph Node Washout
Melanoma of Unknown PrimaryRecurrent MelanomaStage IIIB Cutaneous Melanoma AJCC v7

Ipilimumab or High-Dose Interferon Alfa-2b in Treating Patients With High-Risk Stage III-IV Melanoma That Has Been Removed by Surgery

ACTIVE NOT RECRUITING
NCT01274338Phase PHASE3National Cancer Institute (NCI)Started 2011-05-25
IpilimumabQuality-of-Life AssessmentRecombinant Interferon Alfa-2b
ITP - Immune Thrombocytopenia

"Cytotoxic T Lymphocyte-Associated Antigen-4 (CTLA-4) Gene Single-nucleotide Polymorphism in Primary Immune Thrombocytopenic Purpura in Children"

NOT YET RECRUITING
NCT07014904Sohag UniversityStarted 2025-08-20