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
Walter Reed Project, Kenya Medical Research Institute, Kisumu, Kenya; Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, MD, United States; Operational Medicine Department, Division of Medicine, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, United States; Walter Reed Project, Kenya Medical Research Institute, Kisumu, United Nations Avenue Gigiri, Village Market, Nairobi 00621, Kenya
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. Copyright © Informa Healthcare USA, Inc.
hemoglobin A2; hemoglobin F; hemoglobin kenya; hemoglobin variant; malaria vaccine; unclassified drug; adult; article; clinical article; data analysis; diagnostic procedure; endemic disease; female; gene deletion; gene mutation; high performance liquid chromatography; human; ion exchange chromatography; Kenya; malaria; male; mass screening; molecular weight; polymerase chain reaction; preschool child; Adolescent; Adult; Child, Preschool; Chromatography, High Pressure Liquid; Cohort Studies; Endemic Diseases; Female; Fetal Hemoglobin; Hemoglobin A2; Hemoglobinopathies; Hemoglobins, Abnormal; Humans; Infant; Kenya; Malaria; Male; Polymerase Chain Reaction