In a study searching for candidate genes in skeletal muscle from 195 patients with schizophrenia medicated with SGAs, a moderate association was found between the polymorphism rs9852 variant in TBC1 domain family member 1 protein (TBC1D1), a Rab-GTPase that regulates GLUT4 trafficking, and lowers weight gain, although the functional relevance is unknown [156]. Here, TBC1D1 is linked to schizophrenia.