[Ornithine transcarbamylase deficiency. Biochemical studies in the diagnosis of 4 cases and the identification of carriers].

The biochemical studies for the diagnosis of four cases of OCT deficiency are described: two male sibs, with total enzymatic deficiency and neonatal death, and two symptomatic heterozygous females. The enzymatic activity was determined in hepatic necropsy or duodenal biopsy from these patients and carriers were identified among their relatives. The usefulness of the enzymatic analysis compared with the protein loading test followed by the determination of ammonia and orotic acid for the female carrier detection is discussed, and the interest of their identification to prevent the risk of hyperammonemic crisis with possible neurologic sequels is stressed.