A Case of Methylmalonic Acidemia in a 6-month-old Infant

6개월된 영아에서 발견된 메틸말로닐 산혈증 1례

Methylmalonic acidemia is a rare congenital autosomal recessive metabolic disease. It is caused by blocking in the pathways of isoleucine, valine, threonine, methionine, cholesterol and odd-chain fatty acids to succinyl CoA, resulting in the increase of L-methylmalonyl CoA and methylmalonic acid. In most cases, there are symptoms such as recurrent vomitings, lethargy and laboratory abnormalities including metabolic acidosis and hyperammonemia from the neonatal period. We had a 6-month-old infant with methylmalonyl acidemia who presented with recurrent vomiting episodes since 3 months of age, failure to thrive and developmental delay. The laboratory findings showed hyperammoninemia and ketotic metabolic acidosis. Plasma amino acid analysis showed nonspecific finding. Urine organic acid ananysis by gas chromatography and mass spectrometry detected large amount of methylmalonic acid excreted in the urine. We restrained the supply of protein in the amount of 1~1.5 g/kg of body weight a day using leucine, isoleucine and valine-r-estrained milk and administered vitamine $B_{12}$, in the amount of 1mg per day. During the follow-up in the outpatient clinic, He could control his head and showed increased muscle strength.

저자들은 출생 3개월 경 모유에서 분유로 수유를 바꾸면서 시작된 반복되는 구토, 탈수, 성장장애, 대사성 산증, 고암모니아혈증을 보이는 6개월된 남아에서 메틸말로닐 산혈증으로 진단하고 단백질 제한 식이와 비타민 $B_{12}$ 투여로 호전을 보이고 있는 환아 1례를 경험하였기에 문헌고찰과 함께 보고하는 바이다.