A new gene deletion involving the alpha 2-, alpha 1-, and theta 1-globin genes in a black family with Hb H disease.

A new deletion of approximately 8.5 kb that includes the alpha 2-, alpha 1-, and theta 1-globin genes was detected in a father and newborn son of a black family from Georgia. In the newborn baby the chromosome with the deletion occurred together with a rightward (-alpha 3.7) deletion chromosome. The resulting Hb H disease was detected at birth by the high level of Hb Bart's; a moderate anemia with severe microcytosis and hypochromia was present at the age of 5 months. A review of cord blood testing results for a period of over 20 years, involving at least 200,000 black newborns, indicated that this baby was the first with a level of Hb Bart's in excess of 10-15%; this underscores the rarity of alpha-thalassemia-1 in this population.