The Australian type of nondeletional G gamma-HPFH has a C-->G substitution at nucleotide -114 of the G gamma gene.

Nondeletional hereditary persistence of fetal haemoglobin (HPFH) results in the continued production of 2-25% haemoglobin F (Hb F) in the adult who is heterozygous for this mutation. This increase is associated with single-base mutations in the promoter region of either the G gamma- or A gamma-globin genes. Affected positions include -202, -175, -161, -158 and -114 of the G gamma gene, and -202, -198, -196, -195, -175, and -117 of the A gamma gene. There is now evidence that these mutations produce their effect by changing the binding of certain regulatory proteins. We describe a novel C-->G transversion at position -114 of the G gamma gene which is associated with the phenotype of G gamma-HPFH.