The BDNF gene (OMIM ID: 113505) encoding brain-derived neurotrophic factor (BDNF) and the LEP gene (OMIM ID: 164160) encoding leptin (LEP) were found to have a significant association with insulin resistance in ASD patients taking risperidone, suggesting a genetic biomarker for predicting insulin resistance in ASD patients. This evidence concerns the gene LEP and Insulin resistance.