Pharmacogenetics of weight gain in young people treated with Risperidone

Abstract

Aim/Objective: To investigate the association between weight gain and specifi c genotypes in young people treated with risperidone. • To genotype three specifi c genes (HTR2c receptors, LEP and LEPR) which are thought to be likely candidates for association between risperidone and weight gain. • To assess the association between the genotypes of each gene and weight gain. Methods: A retrospective multicentre study was conducted in outpatient mental health clinics/hospitals in the UK and the Kingdom of Saudi Arabia. Analysis was undertaken using TaqMan technology for genotyping and for statistical analysis, SPSS 21 for Windows was used. Results: 200 patients were genotyped, and 197 genotypes were successfully “Called”. All genotyping passed Hardy-Weinberg checking. For all genes, we found no signifi cant association with risperidone –induced weight gain after controlling for baseline weight, age, diagnosis and ethnicity. Signifi cant association was found between baseline BMI-Z, patients with a lower baseline BMI gaining more weight; age at onset of risperidone treatment (p<0.005), younger patients tending to gain more weight (p<0.005) for all 5 SNPs tested, and a signifi cant association between weight gain and ethnicity, individuals of Arab origin being more likely to gain weight than Caucasians (p=0.011- p=0,014) for all SNPs. No association with gender was found for any genotypes. Conclusion: In this sample there does not appear to have been a signifi cant association with risperidone-induced weight gain and any of the genotypes tested. Further studies exploring ethnic variations and age at onset of treatment are warranted, and a larger sample may have yielded more signifi cant results.