Out of the 23 OTC deficiency patients, 21 (91.3 %) were male, resulting in a total of about 60 % male patients included in the study, despite the fact that slightly more female than male patients were included with CPS1 and ASS deficiencies (63.6 and 55.6 %, respectively). This evidence concerns the gene CPS1 and ornithine carbamoyltransferase deficiency.