Hb Kenya among Luo Adults and Young Children in Malaria Holoendemic Western Kenya: Screened by High Performance Liquid Chromatography and Confirmed By Polymerase Chain Reaction

Abstract

Hb Kenya, a fusion hemoglobin (Hb) resulting from a crossover between the ^Aγ- and β-globin genes, is accompanied by an increased level of fetal Hb (Hb F) in adult life. This study describes the use of cation exchange high performance liquid chromatography (HPLC) in the identification of Hb Kenya and of a polymerase chain reaction (PCR) method for confirmatory diagnosis. Data came from 584 children and 406 adults who were screened for eligibility for malaria vaccine trials at Kombewa, Western Kenya. Sixteen subjects (13 children and three adults) had elevated Hb F (5.0–28.4%; normal <5.0%). Of these, 11 had an apparent markedly elevated Hb A₂ (9.2–22.9%) and were confirmed by gap-PCR as having the 22.7 kb deletion characteristic of Hb Kenya. Of the five cases with elevated Hb F but normal A₂, none had Hb Kenya. We propose that in this population, the finding by cation exchange HPLC of an elevated Hb F (>9.0%) and of an apparently increased Hb A₂ (>9.2%), may suggest the presence of Hb Kenya. However, given the inability of differentiating Hb Kenya from a truly elevated Hb A₂ by routine cation exchange HPLC, it is imperative to confirm the Hb Kenya mutation by gap-PCR.

Keywords:

• Hb Kenya
• Hereditary persistence of fetal hemoglobin (HPFH)
• Polymerase chain reaction (PCR) diagnosis
• Cation exchange high performance liquid chromatography (HPLC)