Urea cycle disorders: clinical experiences compared.

A series of cases from 14 Italian Centers

Abstract

Protein and amino acids homeostasis depends on complex anabolic and catabolic-oxidative processes. In adults, the estimated daily protein turnover is 250-400 g, largely exceeding dietary protein intake (50-80 g/day).1 The urea cycle is a fundamental metabolic pathway for detoxification of ammonia derived from protein catabolism. Localized exclusively in the liver, it is characterized by a series of successive mitochondrial and cytosolic reactions that lead to the production of urea.
Within the complex context of inherited metabolic diseases, defects in the urea cycle represent an important cause of mortality and morbidity, with highly specialized clinical-diagnostic and therapeutic implications. In particular, patients affected by severe mitochondrial (and in some cases cytosolic) defects in the urea cycle present neonatal hyperammonemic coma, representing an absolute neonatal metabolic emergency.