Lack of association between antipsychotic-induced Parkinsonism or its subsymptoms and rs4606 SNP of RGS2 gene in African-Caribbeans and the possible role of the medication: the Curacao extrapyramidal syndromes study X.

Recent studies demonstrate an association between antipsychotic-induced parkinsonism (AIP) and rs4606 SNP of RGS2 gene in Jewish and African-Americans. The current study investigates the association between rs4606 and AIP or its subsymptoms (rest tremor, rigidity, and bradykinesia) in 112 psychiatric inpatients of African-Caribbean origin. Presence of AIP, rigidity, bradykinesia, and tremor was measured by the UPDRS. We applied chi(2) (or Fisher Exact) and logistic regression analyses in several models including rs4606, age, gender, dose of antipsychotics, and anticholinergics, and two other putatively functional SNPs in DRD2 (-141CIns/Del) and HTR2C (Cys23Ser) genes. In contrast to recent literature, we find no evidence for an association between rs4606 and AIP or any of its subsymptoms. We hypothesize that the observed lack of association is due probably to differences in serotonin 2A-receptor affinities of the antipsychotics utilized (in contrast to the other published studies, the majority of our patients utilized typical antipsychotics).