[Analysis of 12 cases with methylmalonicacidemia cblA type].

To explore the clinical feature, genetic variant and clinical outcome of patients with cblA-type methylmalonic acidemia (MMA).Clinical manifestations, therapeutic schedule and prognosis of 12 patients with cblA type MMA were analyzed. MMAA gene variants were analyzed for all patients and their parents.Vomiting, dyspnea and drowsiness were the major clinical features of cblA-type MMA. Eleven patients were vitamin B12-responsive. After treatment, the blood level of propionylcarnitine, ratio of propionylcarnitine/acetylcarnitine, urine level of methylmalonic acid and methylcitric acid have decreased significantly (P< 0.05). Follow-up study showed that 8 patients (66.7%) had normal development, while the rest (33.3%) remained to have various level of mental or movement delay. Fourteen MMAA gene variants were detected, with c.365T>C (p.L122P) being the most common (29.2%). Six novel variants, including c.54delA (p.A19Hfs*43), c.275G>A (p.G92V), c.456delT (p.G153Vfs*8), c.667dupA (p.T223Nfs*4), c.1114C>T (p.Q372X) and c.1137_1138delCA (p.F379Lfs*27) were found.The main clinical manifestations of patients with cblA-type of MMA include vomiting, dyspnea and drowsiness. Most patients are vitamin B12-responsive. c.365T>C is a potential hot spot variant of MMAA gene in China.