OAT (Ornithine Aminotransferase): OAT is a gene that encodes the ornithine aminotransferase enzyme, which plays a crucial role in the urea cycle. This enzyme catalyzes the conversion of ornithine to citrulline, aiding the body in detoxifying ammonia. Mutations in OAT can interfere with this process, resulting in hyperammonemia — a condition characterized by elevated blood ammonia levels that can impact neurological function.