母亲维生素B_(12)缺乏导致婴儿继发性甲基丙二酸尿症的诊断与治疗分析

Diagnosis and treatment of secondary methylmalonic aciduria due to maternal vitamin B_(12) deficiency

目的探讨婴幼儿继发性甲基丙二酸尿症的病因、诊断和治疗.方法对7例继发性甲基丙二酸尿症患儿的临床表现、生化特点、诊疗经过以及其母亲在孕期的健康、营养状况进行回顾性分析.结果患儿于生后1～13个月时因呕吐、惊厥、智力运动发育落后等来院就诊.6例合并轻重不同的贫血,5例合并代谢性酸中毒、肝功能损害,患儿尿甲基丙二酸浓度增高.患儿母亲中4例患慢性胃病,1例患肝胆结石,1例长期素食,患儿母亲血清维生素B12偏低,叶酸降低,同型半胱氨酸增高.经维生素B12、叶酸补充治疗后,患儿全身情况逐渐改善,6例发育正常,1例遗留轻度智力损害.结论母亲慢性胃肠、肝胆疾病及营养障碍可导致维生素B12、叶酸缺乏,引起婴儿继发性甲基丙二酸尿症,早期诊断及维生素B12、叶酸补充治疗是改善预后的关键.

Objective To investigate the causes, diagnosis and treatment of infants with secondary methylmalonic aciduria due to maternal vitamin B 12 deficiency. Methods The clinical, laboratory data and treatment of 7 children with secondary methylmalonic aciduria and their mothers′ health and nutrition were retrospectively reviewed. Results All children were presented to the hospital with vomiting, seizures or mental retardation during 1 to 13 months after birth. Varied degrees of anemia was found in 6 infants and 5 with metabolic acidosis and liver dysfunction. Methylmalonic aciduria was found in all subjects. Four of the mothers had chronic gastritis, one with gallstones in liver and gallbladder and one was a vegetarian. Decreased serum level of vitamin B 12 and folic acid and elevated homocystine concentrations were found in all mothers. After vitamin B 12 and folic acid supplementation, significant improvement was observed in all patients. Six infants showed normal development and one had mild mental retardation. Conclusions Chronic gastritis, liver/gall bladder diseases or being a vegetarian might lead to maternal vitamin B 12 deficiency and then infantile secondary methylmalonic aciduria. Early diagnosis and vitamin B 12 and folic acid supplement are crucial in improving the prognosis.