Clinical and variant analysis of 15 patients with methylmalonic acidemia / 中华医学遗传学杂志

ABSTRACT

OBJECTIVE@#To report on clinical characteristics and genetic findings in 15 Chinese patients with methylmalonic acidemia (MMA).@*METHODS@#For the 15 MMA patients detected by tandem mass spectrometry, genetic analysis was carried out in twelve pedigrees. Clinical characteristics, genetic finding, treatment and outcomes were retrospectively analyzed.@*RESULTS@#The main features of the patients included poor feeding, recurrent vomiting, lethargy, seizure and development retardation. Blood propionylcarnitine (except for 3 patients), its ratio with acetylcarnitine, and urine methylmalonic acid were increased in all patients. Twelve patients were diagnosed genetically, which included 7 with MUT variants, 4 with MMACHC variants, and 1 with MMAB variant. Nine MUT variants were detected, among which c.1159A>C, 753+1delGinsTGGTTATTA and c.504del were novel. Six known pathogenic MMACHC variants and two novel MMAB variants (c.289_290delGG, c.566G>A) were also detected. Seven patients died of metabolic crises within a year, others had improved effectively following the treatment, but had mild to severe growth delay and/or developmental retardation.@*CONCLUSION@#The clinical manifestation of MMA are complex. Most patients have variants of the MUT and MMACHC genes. High mortality may occur before one year of age.