Normal total lymphocytes counts.Low percentages of CD4+ (16%; RV: 28.4-44.4***) and CD19 (3%; RV: 4-33*).IgA deficiency (<7 mg/dL; RV: 45-236**) with normal IgG and IgM**.Moderately reduced proliferation assays.Poor weight gain, mitral stenosis, pulmonary hypertension, mild motor and speech delay, recurrent infections, hearing loss, lymphadenopathies, dysmorphic features. This evidence concerns the gene CD4 and pulmonary arterial hypertension.