The three genes are called the apolipoprotein L1, L2, and L4 genes. The apolipoprotein L family of genes makes lipoproteins, which in turn play a central role in cholesterol transport. Cholesterol is important in cellular processes during brain development and in the adult brain. The fact that the apolipoprotein L1, L2, and L4 genes are on expression overdrive in brains of people with schizophrenia suggests that they might play a causative role in schizophrenia, Bahn told Psychiatric News.