CTLA-4 Y218* mutation in four generations of a family. (A) Pedigree of the affected family, with proband identified by the arrow (patient 16); filled symbols signify clinically affected family members, with the heterozygous CTLA4 c.654T>A, p.(Tyr218*) variant noted in individuals who harbor it. WT denotes family members sequenced and found to have no mutation. Squares represent males, and circles represent females; a diagonal line (as in family member 5) indicates a deceased individual. (B) Biopsy of the terminal ileum from P12 showing diffuse lymphocytic infiltrates (arrows).