Acetyl-Coenzyme A acetyltransferase 2 is an enzyme involved in lipid metabolism. Reported patients with ACAT2 deficiency have shown severe mental retardation and hypotonus. The ACAT2 gene shows complementary overlapping with the 3-prime region of the TCP1 gene in both mouse and human. These genes are encoded on opposite strands of DNA, as well as in opposite transcriptional orientation.