Orthotopic liver transplantation for ornithine transcarbamylase deficiency with hyperammonemic encephalopathy.

Ornithine transcarbamylase (OTC) deficiency is an X chromosome-linked disorder causing hyperammonemic encephalopathy with a very poor prognosis. We describe here two patients with OTC deficiency, one a late on-set female patient (case 1) and the other a neonatal-onset male patient (case 2), who were successfully treated with orthotopic liver transplantation (OLTx). The OTC activity in the excised liver was 10% and 0% of control, respectively. Hyperammonemic encephalopathy was controlled with medical therapy in case 1 until the of 5 years, but the complicated course in case 2 in which hyperammonemia required peritoneal dialysis and hemodialysis in the neonatal period necessitated OLTx with a reduced-size liver at the age of 80 days. Both patients had restoration of serum ammonia level to normal in 2 and 3 days after liver replacement, and both patients have normal neurological and developmental status after 2 and 0.5 years of postoperative follow-up. These cases illustrate not only the metabolic cure of this disorder, but also the need to preserve neurological integrity by aggressive medical management of the hyperammonemia preoperatively and early surgical intervention when indicated, even if this is required very early in life.