A Case of Dietary Treatment of Vitamin B12 Non-responsive Methylmalonic Acidemia

Song, Won Young; Kim, Ki Soo; Yoo, Han Wook

Abstract

Methylmalonic acidemia is a metabolic disorder of amino acid and fatty acid metabolism. A Female infant, who was diagnosed as methylmalonic acidemia based on findings; methylmalonic aciduria, metabolic acidosis with increased anion gap, hyperammonemia, has been followed up for 9 months. She has been placed on the planned diet according to Ross metabolic formula nutrition support protocol. The diet is composed of protein 2.0g/kg/day, ILE 80mg/kg/day, MET 30mg/kg/day, THR 75 mg/kg/day, VAL 85mg/kg/day and total calorie 115Cal/kg/day with the distribution of protein: carbohydrate: fat = 1: 4: 5. The practical dietary prescription consisted of whole milk 8.6g, OS-1 2.1g, glucose 7.1g, rice 3.6g and vegetable oil 0.7ml per each 100ml of liquid diet. After the administration of specially prescribed amino acid mixture, OS-1, her body weight caught up from less than 3 percentile at 3 month to 50 percentile at 9 month. Plasma levels of amino acids, ILE, MET, THR, VAL were maintained within normal values. However, her development lagged 3-4 months behind the developmental milestones appropriate for her chronological age. The plasma ammonia and bicarbonate levels were normalized. The urinary excretion of methylmalonic acid has been markedly decreased during follow-up. We could maintain the patient,s growth and biochemical indices within normal range by prescribing specially made amino acid mixture. However, the development seemed to be delayed inspite of strict metabolic controls, it indicating that further long term follow-up is needed.