Gonzalez et al. (1977) reported 2 families, with surnames beginning with W and T, in which multiple members had severe hypoplastic anemia, congenital anomalies, and leukemia. Important characteristics differentiating this condition from Fanconi anemia (227650) were autosomal dominant ... Gonzalez et al. (1977) reported 2 families, with surnames beginning with W and T, in which multiple members had severe hypoplastic anemia, congenital anomalies, and leukemia. Important characteristics differentiating this condition from Fanconi anemia (227650) were autosomal dominant inheritance and absence of chromosome breakage. In addition, the congenital anomalies were somewhat different. The W family was ascertained through a 13-year-old girl without congenital anomalies who developed acute lymphocytic leukemia at the age of 11.5 years. Her father had clinodactyly V bilaterally and at 26 years was found to have pancytopenia refractory to treatment and leading to death 1 year later. His oldest brother was born with congenital malformation of the elbow and hands and was healthy until age 38 when he was found to have idiopathic anemia evolving into refractory pancytopenia. He died at 42 years of age. Their mother had died at age 71 of leukemia. The propositus of the T family had malformations of both hands at birth and at 21 months was found to have anemia for which he received transfusions. Several paternal relatives had severe hand anomalies and a history of childhood anemia. The paternal grandfather died at the age of 51 of acute monocytic leukemia. Gonzalez et al. (1977) concluded that some earlier reports of presumed Fanconi anemia actually are instances of the WT syndrome. For example, McDonald and Goldschmidt (1960) reported 3 children and their mother who had severe anemia in childhood. All the children had abnormal thumbs. McDonald and Mibashan (1968) reported that 2 of the children recovered spontaneously from serious hematologic abnormalities. Smith et al. (1987) described a third family. The 13-year-old male proband, referred for evaluation of possible Fanconi anemia, had bilateral absent thumbs with flexion contractures of the fingers, irregular hyperpigmentation, radioulnar synostosis, and bilateral sensorineural hearing loss. The karyotype was 47,XXY; cytogenetic studies using clastogenic agents were negative. Nine other members of the family spanning 3 generations were affected with findings ranging from transient to chronic anemia and/or radial defects of digitalized, hypoplastic or absent thumbs. Of 10 affected individuals, 4 had both hematologic and radiologic abnormalities and 5 had only radial defects. Shahidi (1987) gave comparisons with Fanconi anemia and dyskeratosis congenita (305000).