Identification of 2 WAS mutations. (A) Sequence analysis of P1 demonstrating 36201T>C leading to Ile294Thr. (B) Sequence analysis of P2 demonstrating 36143T>C leading to Ser272Pro. (C) Confirmation of the presence of the T>C mutation in P1 by PCR and DdeI restriction endonuclease digestion. Lane 1: undigested PCR product, lane 2: P1, lane 3: patient's sister (clinically healthy), lane 4: mother, lanes 5 and 6: healthy controls, and lane 7: water. (D) Confirmation of the T>C mutation in P2 by PCR and BpmI restriction endonuclease digestion. Lane 1: P2, lane 2: mother, lane 3: father, lane 4: maternal aunt, lane 5: maternal grandmother, lane 6: maternal uncle, and lane 7: DDW.