Differential gene expression in TG mice encompassed a downregulation of several genes associated with schizophrenia and autism spectrum disorder, including Setd1a, Cacna1g, Ank3, and Shank3, as well as a downregulation of histone methyltransferase genes that belong to the Set1-like histone H3 lysine 4 (H3K4) methyltransferase family (Kmt2a, Kmt2b and Kmt2d). The gene discussed is KMT2D; the disease is autism spectrum disorder.