Acute metabolic decompensation episodes were analyzed during follow-up in the evaluable population only (n = 66, as 13/79 patients were excluded due to the lack of information regarding treatment intake), of whom 48 had an OTC deficiency, and 11, 4, and 3 patients had CPS1, NAGS, and ORNT1 deficiencies, respectively. Here, CPS1 is linked to ornithine carbamoyltransferase deficiency.