OTC deficiency

Gene Therapy of Ornithine Transcarbamylase Deficiency

Ornithine transcarbamylase (OTC) deficiency is the most common urea cycle disorder with an incidence rate of 1:80,000 births in Japan (1). It occurs when a mutant enzyme protein (OTC) impairs the reaction that leads to condensation of carbamoyl phosphate and ornithine to form citrulline. This impairment leads to reduced ammonia incorporation, which, in turn, causes hyperammonemia. Ammonia is especially damaging to the nervous system, so ornithine transcarbamylase deficiency causes neurological problems as well as eventual damage to the liver.