ABSTRACT
The most classic of the infantile urea cycle presentations is that of ornithine transcarbamylase (OTC) deficiency in the male. Onset is in the neonatal period with coma and or convulsions, and in the absence of effective intervention it is rapidly fatal. A small number of males with variant enzymes has a milder and later presentation. Females who have two X chromosomes have varying phenotypes depending on the proportion of active and inactive X chromosomes.
