Otc, associated with the urea cycle, is an X-linked gene. Mutations in the Otc gene cause Otc deficiency, an inherited urea cycle disorder. The urea cycle is crucial for the detoxification of ammonia, converting it into urea for excretion [1].

In a cohort of 130 families (289 females) with Otc deficiency, 22% of heterozygous females were clinically affected, with different forms of the disease like episodic, chronic, or neonatal. Overall mortality rate was 4%. Ninety disease-causing variants were found, 27 of which were novel. Mutations were classified as "mild" or "severe." A serious disease occurred in 32% of females with a severe mutation compared to 4% in females with a mild mutation, which can assist in prenatal diagnosis for heterozygous females and genetic counseling [1].

In conclusion, the Otc gene is essential for the proper functioning of the urea cycle. Genetic studies in the context of Otc deficiency, especially the analysis of mutations in female cohorts, help in understanding the phenotype-genotype correlation. This knowledge is valuable for prenatal diagnosis and genetic counseling related to this X-linked disorder [1].