The analysis of the relationship between blood Leucine levels at diagnosis and Leucin Tolerance in maple syrup urine disease

Introduction and Aim: Maple Syrup Urine Disease (MSUD) is a congenital metabolic disease with autosomal recessive transmission. The aim of this study is to analyze the relationship between blood leucine levels at diagnosis and future leucine tolerance and to discover whether any prediction about the future leucine tolerance is possible by evaluating blood leucine levels at diagnosis. Materials and Methods: 45 cases were included within the study. Diagnostic leucine values of different age groups were compared with age at diagnosis, leucine tolerances, maximum leucine levels/ages, average blood leucine levels and disease follow-up points. Results: Average diagnostic leucine levels were 2215.89±1161.39 µmol/L. Median age at diagnosis was 17 days. The relationship between diagnostic leucine levels and the age at diagnosis was not significant. The relationship between diagnostic leucine levels and leucine tolerance was not significant. There were no significant relationship between diagnostic leucine levels, maximum blood leucine levels, age at maximum blood leucine levels and disease follow-up points. The average blood leucine level was 290.09±133.21 µmol/L and it showed no significant relationship with diagnostic leucine level. Conclusion: Prognosis of disease cannot be foreseen on the basis of diagnostic leucine levels. The maximum blood leucine level may rather be seen in the first three years of life. During this period, treatment should be carried out meticulously. MSUD should be included in the neonatal screening to establish an early diagnosis. Leucine tolerance per kilogram is prone to decrease until 8 years of age, and is more stable afterwards. Leucine tolerance may be predicted to stay at the same level afterwards.