The relationship between CYP2D6 polymorphisms and Tardive Dyskinesia in black Zimbabwean psychotic patients on typical antipsychotics

Abstract

CYP2D6 polymorphisms have been associated with different drug efficacies and adverse effect profiles including Tardive Dyskinesia (TD). The occurrence of these polymorphisms has also been noted to be different amongst different racial or ethnic groups. In Asians and Caucasians CYP2D6*10 and CYP2D6*3, *4 and *5 have been positively associated with TD respectively. In Africans no clear relationships with the prevalent reduced function CYP2D6 genotypes has been shown. The objective of this study was to determine whether occurrence of TD is associated with the most prevalent reduced function CYP2D6 genotypes in black Zimbabweans – CYP2D6*17 and *29. AIMS scoring and CYP2D6 genotyping was carried out on patients exposed to first generation or typical antipsychotic medications at Parirenyatwa Annexe and Harare Psychiatric units in an unmatched case control study. The main outcome measures were CYP2D6*17 and *29 genotypes. The relationship between TD and mutant CYP2D6*17 homozygote and heterozygote genotypes was not statistically significant with p values of 0.740 and 0.442 in the haloperidol exposed and 0.587 and 0.150 in those exposed to haloperidol, FD and CPZ respectively. No CYP2D6*29 result could be determined due to a failure in genotyping for this SNP. The results presented suggest no association between the major reduced function CYP2D6 allele *17 and TD in black psychotic Zimbabwean patients.