STOP//A case of pregnancy with methylmalonic acidemia combined with homocysteinemia (cblC type)

Combined methylmalonic aciduria (MMA) and homocystinuria, cblC type, is the most common MMA in China. MMA’s clinical phenotype is complex and diverse. Patients with late-onset disease usually have a milder condition and the opportunity to have children. This article reports a successful pregnancy and delivery of an MMA (cblC type) patient in China. The patient was found to have hyperhomocysteinemia due to intracranial venous sinus thrombosis in 29 years old. Further examination suggested MMA. Genetic testing showed MMACHC c.80A>G from the father and c.609G>A from the mother, and the diagnosis was combined MMA (cblC type). During pregnancy, the patient continued to supplement cobalamin, L-carnitine, betaine, etc., and maintained a normal diet without restricting protein intake. The primary disease and fetal growth were normal during pregnancy. At 32+ weeks of gestation, she experienced unexplained vomiting and underwent cesarean section at 33+ weeks of gestation. The mother and baby had a good outcome. Adult MMA patients have the opportunity to have children. There are no clear reference treatment plans for the primary disease and prenatal care during pregnancy, and more case reports are needed to accumulate experience.