Five families with homozygous delta-thalassaemia in Japan.

Five families with delta-thalassaemia discovered in Ehime, Japan, are presented. The delta-thalassaemia was associated with a slight elevation of the level of Hb F in two families and with normal Hb F levels in three. Complete absence of HbA2 was found in the homozygous probands. No abnormal clinical or haematological findings were noted in the individuals with delta-thalassaemia.