Case#: Patient 6 (P6) is an 18-year-old Chinese male.

DiseaseAssertion: Patients are asserted to have "CTLA4 haploinsufficiency (CTLA-4 h).

FamilyInfo: Patient denied family history of inborn error of immunodeficiency. The patient's father harbors the same CTLA4 variant as the patient. No symptoms are reported in the patient's father.

CasePresentingHPOs: HP:0001954 (Recurrent fever), HP:0012735 (Cough), HP:0002829 (Arthralgia), HP:0002113 (Pulmonary infiltrates), HP:0002716 (Lymphadenopathy), HP:0006532 (Recurrent pneumonia), HP:0004313 (Decreased circulating immunoglobulin concentration

CaseHPOFreeText: MRI of knees showed patchy abnormal signals in the right femoral and lateral condylar regions suggestive of bone marrow edema, with surrounding soft tissue edema. Mild joint effusion and suprapatellar bursa fluid were also noted. Treatment with avatacept was started and at the six-month follow-up the patient reported clinical improvement. He had no fever or sputum production and symptoms of lymphadenopathy and joint pain had improved.

CaseNotHPOs: HP:0001386 (Joint swelling), HP:0000988 (Skin rash), HP:0002014 (Diarrhea), HP:0003493 (Antinuclear antibody positivity), HP:0034092 (Anti-cyclic citrullinated peptide antibody positivity), HP:0002923 (Rheumatoid factor positive), HP:0032230 (Cytoplasmic antineutrophil antibody positivity)

CaseNotHPOFreeText:

CasePreviousTesting: None noted.

GenotypingMethod: Genotyping was performed via whole exome sequencing.

PreviouslyPublished No prior article is known to contain information on the same proband.

Variant: The patient is heterozygous for the NM_005214.4 CTLA4):c.436G>A(p.Gly146Arg) variant.

ClinVar: 849622

gnomAD: This variant has an allele frequency of 0.000001696 in gnomAD v4.1.1. (https://gnomad.broadinstitute.org/variant/chr2-203870912-G-A?dataset=gnomad_r4)

SupplementalData: There is no supplemental data.