关键词: 甲基丙二酸, 维生素B₁₂, 气相色谱-质谱法

Abstract: Objective To explore the clinical characteristics and treatment of neonatal methylmalonic academia(MMA). Method The clinical data of 7 patients with neonatal MMA were analyzed and the diagnoses were confirmed by gas chromatography-mass spectrometry(GC/MS). Results The patients consisted of 3 males and 4 females, whose age of onset ranged from 0 to 6 days with all 7 cases early in the first week after birth.The main clinical manifestations were weak reaction(6 cases), poor feeding(7 cases), hyperpnea(3 cases), convulsion(2 cases), hypotonia(7 cases), et al.6 cases presented with thrombocytopenia.The laboratory findings showed metabolic acidosis in 6 cases, hyperammonemia in 4 cases and remarkable elevation of urinary methylmalonicacid concentration in all cases.Some abnormalities were noted by the brain CT or MR in 2 cases of 5.2 cases died at a short time after giving up therapy, 1 case died at the age of 3-month after giving up therapy, 1 case follow-up failed to.2 cases received therapy of vitamin B₁₂ and supplementation of L-carnitine with restricted-protein diet and showed a favorable outcome with no symptoms for a period ranging from 1 year to 1 years and 9 months.1 case received therapy of vitamin B₁₂ and supplementation of L-carnitine with restricted-protein diet, but no effect and died at the age of 4-month. Conclusions The clinical manifestations of neonatal MMA are nonspecific.GC/MS can be used to confirm the diagnosis.Early diagnosis and early treatment is the key to improve the prognosis.

Key words: methylmalonic acid, vitamin B₁₂, mass fragmentography