The authors describe a family with two children with microcephaly and normal intelligence, in which acute lymphoblastic leukemia developed in one of the siblings. An autosomal recessive pattern of inheritance is suggested by the pedigree. This is consistent with the literature, which the authors reviewed. All of the patients have similar phenotypic features, with some demonstrating chromosomal instability. It is important to recognize this syndrome because of the increased risk of lymphoreticular malignancy.