1. Three siblings with Hb H thalassemia disease have been observed in a family in which 17 members from 3 generations have been examined. Four additional family members have α-thalassemia minor.
2. A genetic examination of the family provides further evidence for the theory that Hb H thalassemia disease is due to the interaction of the α-thalassemia gene and another "silent" gene which, however, does appear to produce minor morphologic abnormalities when present alone.
3. Reevaluation of the effects of splenectomy indicate that this procedure may be of significant benefit only in the more severe cases of Hb H disease.