Abstract:

Objective To explore the clinical characteristics, laboratory examination and genotype of mut-type methylmalonic acidemia (MMA) to provide basis for the diagnosis and treatment of mut-type MMA.Methods A retrospective analysis of clinical manifestation, general examination, serum and urine metabolism, gene detection results of 18 children with mut-type MMA admitted to the pediatric endocrinology, genetics and metabolism clinic of the Second Hospital of Hebei Medical University from December 2015 to June 2020 was performed.Results Mut-type MMA were common in less than 1 year infant, in those patients, main clinical manifestations presented vomiting, drowsiness, even convulsions, dyspnea and disturbance of consciousness in severe. Gene mutation of 18 children was caused by methylmalonyl-CoA mutase (MUT), detecting totally 20 mutations; the mutation sites were mainly c.729_730insTT, and with diversification of mutation types.Conclusion Mut-type MMA, a atypical clinical manifestations, should be reference urine metabolism, genetic testing is considered to be a reliable evidence for clinical classification with diversification of mutation types.

Key words: methylmalonic acidemia, MUT gene, mut type