Cytochrome P450 CYP2C19 genotypes in Nigerian sickle-cell disease patients and normal controls.

BACKGROUND AND
OBJECTIVE: Subjects with different CYP2C19 genotypes may metabolize proguanil, a pro-drug used for malaria prophylaxis differently and the frequency of the different alleles may be different in patients with sickle-cell disease (SCD) and normal controls. The objective of this study was to evaluate CYP2C19 *1, *2 and *3 allele and genotype frequencies in Nigerian normal controls and SCD patients, and to further compare variant CYP2C19 frequencies in Nigerians with other African populations.
METHODS: Genotyping was carried out with PCR and restriction fragment length polymorphism analysis. RESULTS AND DISCUSSION: CYP2C19 *1 (84·3 vs. 84·9%) or *2 allele frequency (15·7 vs. 15·1%) was not significantly different between patients with SCD and normal subjects. No *3 allele was detected in the cohort. The SCD group exhibited a statistically significantly lower frequency of *1/*1 genotype (69·6%) compared with normal controls (74·4%). Frequency of *2/*2 was significantly lower in SCD (0·9%) compared with normal controls (4·7%). Frequencies of *1/*2 (29·6 vs. 20·9%) were no different in SCD and normal controls.
CONCLUSION: Prevalence of CYP2C19 polymorphisms was defined for the first time in Nigerian normal and SCD populations. Nigerian SCD patients exhibited significantly lower CYP2C19 *1/*1 and *2/*2 frequencies than normal controls. No differences were detected in CYP2C19 allele or genotype frequencies in normal subjects between this study and previous reports in other African populations.