A critical reappraisal of dietary practices in methylmalonic acidemia raises concerns about the safety of medical foods. Part 1: isolated methylmalonic acidemias (original) (raw)

2015, Genetics in Medicine

PURPOSE-Medical foods for methylmalonic and propionic acidemias (MMA/PA) contain minimal valine, isoleucine, methionine and threonine, but have been formulated with increased leucine. We aimed to assess the effects of imbalanced branched-chain amino acid intake on metabolic and growth parameters in a cohort of MMA patients ascertained via a natural history study. METHODS-Cross-sectional anthropometric and body composition measurements were correlated with diet content and disease-related biomarkers in 61 patients with isolated MMA (46 mut, 9 cblA and 6 cblB). RESULTS-Patients with MMA tolerated close to the recommended daily allowance (RDA) of complete protein (mut 0 : 99.45 ± 32.05% RDA). However, 85% received medical foods, the protein-equivalent in which often exceeded complete protein intake (35%). Medical food consumption resulted in low plasma valine and isoleucine concentrations, prompting paradoxical supplementation with these propiogenic amino acids. Weight and height-for age Z-scores correlated negatively with the leucine/valine intake ratio (r=−0.453, P=0.014, R 2 =0.209 and r= −0.341, P=0.05, R 2 =0.123, respectively). Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: