MST1 mutations in 2 families. (A) Pedigrees of 2 families presenting a CID syndrome. Consanguinity is indicated by double horizontal bars. Black boxes and circles represent affected males and females, respectively. Diagonal bar indicates deceased subjects. An identification number was assigned to each patient. (B) Semilogarithmic graph representing the progressive CD4 T-cell lymphopenia (left) and the marked loss over time of naive CD4 CD45RA⁺ T cells (right) observed in MST1-deficient patients. (C) Schematic representation of the MST1 protein. Mutations identified in the families are indicated by arrows.