Background: Urea cycle disorders (UCD) and organic acid disorders classically present in the neonatal period. In those who survive, developmental delay is common with continued risk of regression. Liver transplantation improves the biochemical abnormality and patient survival is good. We report the neurocognitive and functional outcomes post-transplant for nine UCD, three maple syrup urine disease, and one propionic acidemia patient.
Methods: Thirteen inborn errors of metabolism (IEM) patients were individually one-to-two matched to 26 non-IEM patients. All patients received liver transplant. Wilcoxon rank sum test was used to compare full-scale intelligence-quotient (FSIQ) and Adaptive Behavior Assessment System-II General Adaptive Composite (GAC) at age 4.5 years. Dichotomous outcomes were reported as percentages.
Results: FSIQ and GAC median [IQR] was 75 [54, 82.5] and 62.0 [47.5, 83] in IEM compared with 94.5 [79.8, 103.5] and 88.0 [74.3, 97.5] in matched patients (P-value <.001), respectively. Of IEM patients, 6 (46%) had intellectual disability (FSIQ and GAC <70), 5 (39%) had autism spectrum disorder, and 1/13 (8%) had cerebral palsy, compared to 1/26 (4%), 0, 0, and 0% of matched patients, respectively. In the subgroup of nine with UCDs, FSIQ (64[54, 79]), and GAC (56[45, 75]) were lower than matched patients (100.5 [98.5, 101] and 95 [86.5, 99.5]), P = .005 and .003, respectively.
Conclusion: This study evaluated FSIQ and GAC at age 4.5 years through a case-comparison between IEM and matched non-IEM patients post-liver transplantation. The neurocognitive and functional outcomes remained poor in IEM patients, particularly in UCD. This information should be included when counselling parents regarding post-transplant outcome.
Keywords: functional outcomes; inborn errors of metabolism; liver transplantation; neurocognitive outcomes; pre‐school; urea cycle disorder.
© 2020 The Authors. Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM.