Safety and long-term outcomes of early liver transplantation for pediatric methylmalonic acidemia patients

Background LT is a treatment option for MMA patients, but renal function impairment is one of the long-term concerns. The aim of this study was to evaluate the outcomes of early LT in these patients. Methods A total of 11 MMA mut-type patients (including 10 mut0 cases and 1 mut-case) who received LT in our institute were reviewed. Their metabolic profiles were compared between the pre/post-transplant periods. Their immunosuppressant and renal function changes after transplantation were assessed. Results After a mean follow-up of 97.5 +/- 38.4 months, there were two deaths, and the actual survival rate was 81.8%. Their metabolic profiles had improved (mean blood ammonia level 366.8 +/- 105.5 vs. 53.1 +/- 17.4 mu g/dl, p < .001; C3/C2 ratio 2.68 +/- 0.87 vs. 0.73 +/- 0.22, p = .003; mean urine MMA level 920.5 +/- 376.6 vs. 196.2 +/- 85.4, p = .067), and hospital stays were decreased (78.8 +/- 74.5 vs. 7.4 +/- 7.0 days/year, p = .009) after transplantation. The mean age at transplant was 1.81 +/- 2.02 years old, and nine of these patients received LT before the age of 1.5 years old (early LT). Under prospective immunosuppressant dose reduction, three of these early LT patients discontinued the drug and were sustained for more than 5 years. Most of the patients had a preserved renal function, and no patient is currently on dialysis. Conclusions In addition to the improvement in the metabolic parameters, early LT in MMA patients may allow for a dose reduction of the immunosuppressant, and the patient's renal function could be preserved in the long term.