Identification of a SH2B3 mutation in a familial autoimmunity and acute leukemia kindred. (A) Family pedigree. Affected individuals are shaded in black. (B) DNA sequencing chromatograms showing the SH2B3 D231fs mutation in the proband and a heterozygous carrier compared with a control SH2B3 wild-type DNA sample. (C) Schematic representation of the structure of the SH2B3 protein. The phenylalanine zipper (Phe-ZIP), the Plekstrin homology domain (PH), and the Scr Homology 2 domains (SH2) are indicated. The SH2B3 D231fs mutation identified in this family and somatic SH2B3 mutations found in ALL patient samples are shown.