A novel de novo missense OTC mutation in an Iranian girl: a case report

Ornithine transcarbamylase deficiency (OTCD) is the most common inborn error of the urea cycle, caused by mutations in the OTC gene located on the X chromosome. OTCD presents in early and late-onset forms, with variable severity. Despite the high genetic heterogeneity, genotype-phenotype correlations help in prognosis and treatment planning. This study presents a novel missense mutation in an Iranian girl with OTCD, occurring de novo, contributing to the understanding of the disease's genetic landscape.

A 2-year-old girl from a consanguineous marriage presented with nausea, recurrent vomiting, and seizure. Elevated plasma ammonia, liver enzyme tests, and hepatomegaly suggested metabolic disorders. Following whole exome test, a novel heterozygous missense mutation in exon 7 of the OTC gene (c.674C>T) was identified in the patient. Despite maternal and paternal testing, no mutation was detected.

Identifying new mutations in populations helps mitigate the high mortality rates associated with OTCD hyperammonemic episodes and provides the best course of treatment, especially considering the diverse phenotypic variations.