Serum vitamin B12 is a promising auxiliary index for the diagnosis of methylmalonic acidemia in children: A single center study in China

Background and aims: Vitamin B12 (cobalamin, VitB12) is an essential coenzyme of methylmalonyl-CoA mutase and methionine synthase. Variations in VitB12 metabolism, absorption, transport, or intake may cause changes in methylmalonic acidemia (MMA) biomarkers. We aimed to investigate whether serum Vitamin B12 levels could be used in the early detection of MMA.Materials and methods: We included 241 children with MMA and 241 healthy matched controls. We measured serum VitB12 levels by an enzyme immunoassay and investigated the relationship between abnormal VitB12 levels and hematologic parameters as potential risk factors for MMA symptoms.Results: Compared with controls, the serum levels of VitB12 were increased in the MMA group (p < 0.001). Serum VitB12 distinguished patients with MMA from healthy children (p < 0.001). Serum VitB12 combined with homocysteine and ammonia identified cblC and mut type MMA, respectively (p < 0.001). Homocysteine, folate, ammonia, NLR, and red blood cells contributed to serum VitB12 in cblC type MMA (p < 0.001); homocysteine, ammonia, and red blood cells, contributed in mut type MMA (p < 0.001); and elevated VitB12 was an inde-pendent predictor of MMA clinical onset (p < 0.001).Conclusion: Serum VitB12 can be used as an early diagnostic biomarker for MMA in children.

Automated summary

This study investigated whether serum Vitamin B12 levels could be used as an early diagnostic biomarker for MMA. The results showed that serum Vitamin B12 levels were significantly increased in MMA patients, and serum Vitamin B12 combined with other biomarkers could be used to distinguish different types of MMA. Additionally, elevated Vitamin B12 was found to be an independent predictor of MMA clinical onset.