累及高颈段脊髓导致呼吸衰竭的甲基丙二酸血症一例

Methylmalonic acidemia involving high cervical spinal cord leading to respiratory failure: a case report

晚发型甲基丙二酸血症(methylmalonicacidemia,MMA)是一种少见的遗传代谢病。本病例报道的成年起病的MMA合并高同型半胱氨酸血症患者,女性,46岁。以进行性四肢无力、精神异常起病,并出现排尿困难、呼吸衰竭。神经系统查体四肢肌力下降及锥体束征;血同型半胱氨酸、尿甲基丙二酸水平显著增高;头颈胸腰磁共振成像显示枕骨大孔水平颈髓至腰1椎体水平脊髓内异常信号;基因检测发现MMACHC两处杂合变异:c:609G>A;c:349G>A,符合钴胺素C缺乏型。给予左卡尼汀、维生素B12、甜菜碱等治疗。患者精神症状、四肢肌力和呼吸衰竭均有所好转,血同型半胱氨酸水平也显著下降。

Late onset methylmalonic acidemia(MMA)is a rare genetic metabolic disease.This case is a 46 year old adult patient with MMA complicated with hyperhomocysteinemia.It starts with progressive limb weakness and mental abnormality,and has dysuria and respiratory failure.Neurological examination showed decreased muscle strength of limbs and pyramidal tract sign.The levels of blood homocysteine and urinary methylmalonic acid increased significantly.Head,neck,thoracolumbar magnetic resonance imaging showed abnormal signals in the spinal cord from the level of foramen magnum to the level of lumbar 1 vertebral body.Two heterozygous variants of mmachc were found by gene detection:c:609G>A,c:349G>A,consistent with cobalamin C deficiency.Treat with L-carnitine,vitamin B12 and betaine.The patients′mental symptoms,limb muscle strength and respiratory failure were improved,and the level of blood homocysteine also decreased significantly.