Progresses of diagnosis and therapy in methylmalonic acidemia

Methylmalonic acidemia is an organic acidemia with autosomal recessive heredity,of which the cli- nical presentations are heterogeneous. It is characterized by recurrent vomiting and the neurological symptoms such as lethargy,convulsion,and so on. Diagnosis of this disease depends on the measurement of acylcarnitines in the blood by tandem mass spectrometry and the detection of methylmalonic acid in the urine by gas-chromatography mass spectrometry. The patients with methylmalonic acidemia and homocystinuria should be mainly treated with vitamin B12,betaine and L-carnitine,while the patients with isolated methymalonic acidemia should be treated with protein restriction,the special milk formula without isoleucine,valine,methionine and threonine,as well as the L-carnitine. Compared with the vitamin B_(12)-nonresponsive patients,the vitamin B_(12)-responsive ones have better outcome.