Effect of Swiss-type heterocellular HPFH from XmnI-Gγ and HBBP1 polymorphisms on HbF, HbE, MCV and MCH levels in Thai HbE carriers.

Relationships of Swiss-type heterocellular HPFH as functions of XmnI-(G)γ and HBBP1:rs2071348 polymorphisms and HbF, HbE, MCV and MCH in HbE carriers were evaluated in 52 non-anemic and α-thalassemia-free Thai HbE carriers. HbF and HbE levels were measured using cation-exchange HPLC. MCV and MCH were determined using an automated blood counter. The XmnI-(G)γ polymorphism was identified by XmnI digestion of amplified products, and the HBBP1:rs2071348 polymorphism by tetra-ARMS-PCR. HbF levels in HbE carriers were higher than those in normal individuals. HbF levels >0.8 % indicated the Swiss-type heterocellular HPFH in these subjects, rendering a prevalence of 40.4 %. The XmnI-(G)γ (+) and HBBP1:rs2071348 (C) alleles were modestly positively correlated with elevated HbF, elevated MCH and lowered HbE values. This study thus confirms the influence of the XmnI-(G)γ and HBBP1:rs2071348 polymorphisms on HbF production. The present study demonstrates the association of XmnI-(G)γ and HBBP1:rs2071348 with HbF, HbE, MCV and MCH in HbE carriers for the first time, and highlights the effect of elevated HbF production on HbE levels.