Improved growth and nutrition status in children with methylmalonic or propionic acidemia fed an elemental medical food

Background: Failure-to-thrive (FTT) has been described in patients with organic acidemias treated with low protein diets. Objective: To determine if patients with methylmalonic (MMA) or propionic acidemia (PA) can achieve normal growth and nutrition status. Methods: A 6-month multicenter outpatient study was conducted with infants and toddlers treated with Propimex-1 Amino Acid-Modified Medical Food With Iron (Ross Products Division, Abbott Laboratories, Columbus, OH). Main outcome measures were anthropometrics, protein status indices, plasma retinol, and α-tocopherol. Results: Sixteen patients completed the study. Mean baseline age was 0.54±0.02 years (range 0.03-3.00 years). By study end, mean National Center for Health Statistics (NCHS) weight centile increased from 26 to 49%; mean crown-heel length centile from 25 to 33%; and mean head circumference centile from 43 to 54%. Mean (±SE) protein and energy intakes by <6-month-old, 6<12-month-old, and 1<4-year-old patients were 15.3±0.9g and 645±10kcal; 18.3±1.1g and 741±92kcal; and 25.1±2. 46g and 1062±100kcal, respectively. Plasma glycine concentrations were significantly and negatively correlated with energy intake (r=-0.77, p<0.0005). No correlation was found between dietary protein intakes and plasma ammonia concentrations. Protein status indices, retinol and α-tocopherol concentrations were within reference ranges at study end. Conclusions: Propimex-1 improved growth and nutrition status in patients with MMA or PA in just 6 months when fed in sufficient amounts. Providing energy and protein for patients with FTT at intakes recommended for catch-up growth may have resulted in even better growth.