Hereditary persistence of fetal haemoglobin (HPFH) in conjunction with a chromosomal translocation involving the haemoglobin beta locus.

An HPFH syndrome was found in a woman and her daughter who also carry a 'balanced' cyclic translocation of chromosome segments involving four chromosomes, with one break point located in the region of the Hb beta locus. This HPFH is characterized by 5% and 8% Hb F in peripheral blood, uneven distribution of Hb F in the red cells, and a G gamma/G gamma + A gamma ratio of 0.4. The mapping of the non alpha gene cluster shows no detectable deletion in the entire gamma-delta-beta-globin gene region.