Tau syndrome (thrombocytopenia and absent ulnar) with mental retardation and facial dysmorphy.

A girl with pancytopenia (hemoglobin 9 g. 2,000 PMN. 75,000 platelets) was examined at 23 years of age. She had microcephaly, facial dysmorphy, skeletal deformities (kypho-scoliosis, club feet, club hands) and mental retardation. Puberty was normal, Roentgenograms showed bilateral agenesia of the distal part of the ulna with dislocation of the head of the radius. No other skeletal parts were absent. The condition is probably due to an autosomal recessive gene, the parents being second cousins.