XCI analysis of 20 liver samples of another female OTC deficiency patient, who underwent liver transplantation at the age of 6 years, showed X inactivation ratio ranging from 75:25 to 90:10 in favor of the active paternal X chromosome presumably bearing de novo deleterious splicing mutation in OTC (c.663 + 1G > A). Here, OTC is linked to ornithine carbamoyltransferase deficiency.