This study describes the neurodevelopmental outcome of children with urea cycle disorders (UCD) and organic acidemias (OA) preliver transplant (LT), 1‐year, and 3‐years post‐LT. We performed a retrospective chart review of children with OA or UCD transplanted between January 2014 and December 2021. Standardized motor and cognitive assessment scores were collected from children who had ≥1 motor/cognitive assessment at any timepoint. Pre‐LT brain magnetic resonance imaging (MRI) was graded. Associations between demographic/medical variables and neurodevelopmental outcomes were explored. Twenty‐six children (64% male) underwent LT at a median age of 1.4 (interquartile range 0.71, 3.84) years. Fifteen (58%) had a UCD diagnosis, 14 (54%) required dialysis for hyperammonemia, and 10 (42%) had seizures typically around diagnosis. The proportion of children with gross motor scores >1 standard deviation (SD) below the mean increased across timepoints, and ≥50% demonstrated general intellect scores >2 SD below the mean at each timepoint. The following significant associations were noted: UCD diagnoses with lower general intellect scores (p = 0.019); arginosuccinate lyase deficiency diagnosis with lower visual motor scores at 3‐years post‐LT (p = 0.035); a history of seizures pre‐LT with lower general intellect (>2SD below the mean) at 3‐years post‐LT (p = 0.020); dialysis pre‐LT with lower motor scores (>1 SD below the mean) at 1‐year post‐LT (p = 0.039); pre‐emptive LT with higher general intellect scores at 3‐years post‐LT (p = 0.001). MRI gradings were not associated with developmental scores. In our single centre study, children with UCD or OA had a higher prevalence of developmental impairment post‐LT compared to population norms. Earlier screening, pre‐emptive transplant, and rehabilitation may optimize long‐term outcomes.
