Urea cycle disorders (UCD) are
inborn errors of metabolism caused by deficiency of
enzymes required to convert
nitrogen from
ammonia into
urea. Current paradigms of treatment focus on dietary manipulations,
ammonia scavenger drugs, and
liver transplantation. The aim of this study was to describe the characteristics and indication of
liver transplantation in UCD in a tertiary hospital. We performed a retrospective study of children with UCD seen in the period 2000-2021. Data was collected on clinical onset,
hyperammonemia severity, evolution and
liver transplantation. There were 33 patients in the study period, whose diagnosis were:
ornithine transcarbamylase (OTC, n = 20, 10 females),
argininosuccinate synthetase (ASS, n = 6), carbamylphosphate
synthetase 1 (CPS1, n = 4),
argininosuccinate lyase (ASL, n = 2) and
N-acetylglutamate synthetase (NAGS, n = 1) deficiency. Thirty one were detected because of clinical symptoms (45% with neonatal onset). The other 2 were diagnosed being presymptomatic, by neonatal/family screening. Neonatal forms (n = 14) were more severe, all of them presented during the first week of life as severe
hyperammonemia (mean peak 1,152 µmol/L). Seven patients died (6 at debut) and all survivors received
transplantation. There was no mortality among the late forms. Of the 27 patients who did not die in the neonatal period, 16 (59%) received liver transplantationwith 100% survival, normal
protein tolerance and usual need of
citrulline supplementation. The transplant's metabolic success was accompanied by neurologic sequelae in 69%, but there was no progression of brain damage. Decision of continuous medical treatment in 11 patients appeared to be related with preserved neurodevelopment and fewer metabolic crises.