Abbreviation: HPFH
"Hereditary persistence of fetal hemoglobin" is a genetic condition where adult types of hemoglobin fail to develop and the types of hemoglobin the individual had as a fetus remains present well past the point when they would normally have stopped being produced.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.