AB164. Methylmalonic acidemia/propionic acidemia in Taiwan
Tzu-Hung Chu1, Yin-Hsiu Chien2, Hsiang-Yu Lin3, Hsuan-Chieh Liao4, Huey-Jane Ho5, Chin-Su Liu6, Chih-Jou Lai7, Chuan-Chi Chiang4, Chia-Feng Yang1, Wuh-Liang Hwu2, Shuan-Pei Lin3, Dau-Ming Niu1
Background: Methylmalonic acidemia (MMA) comprises a heterogeneous group of disorders, which are characterized by accumulation of methylmalonate in the body due to deficiency of methylmalonyl/proprionic coenzyme A mutase or defects in the uptake, transport or synthesis of 5'-deoxyadenosylcobalamin. Propionic acidemia (PA) refers to propionyl-CoA carboxylase deficiency. Most these patients might have very-early onset signs and symptoms that occur even before the results of newborn screening (NBS) are available, and die immediately or survive with significant neurodevelopmental disability. The associative outcome of MMA/PA was scarcely reported in Asia.
Methods: From January 2000 to December 2014, elevated C3 and elevated C3/C2 ratio cases were collected from Taipei Institute of Pathology (TIP), Chinese Foundation of Health (CFH) and National Taiwan University Hospital (NTUH). Demographic data, initial presentation, whether or not undergoing liver transplantation (LT) and postoperative prognosis including survival rate, DQ/IQ performance, admission length, tube feeding time and were analyzed.
Results: During this period, 2,735,122 newborns were screened. Overall incidence rate of MMA was 1/109,405; PA, 1/683,781. Referral time was 323 days before the era of NBS vs. 8.8/7.5 days after the introduction for MMA/PA (P<0.05). MMA mutase type generally possesses higher AST, ALT, NH3 value and lower pH value compared to cobalamin type (P<0.05). Seventeen out of 25 MMA mutase type patients received LT; two out of 4 PA patients did LT. Mean admission length shortened from 90.6 days/year (pre-LT) to 9.1 days/year (post-LT) for MMA patients (P<0.0005). Tube feeding ratio decreased from 74.56% to 0.56% (P<0.00005). The anxiety level from the caregiver also down-escalated from 33.4 to 27.2 (P=0.001). DQ/IQ performance ameliorated after LT as well from 50 to 60.1, even though not statistically significant.
Conclusions: There is still room for improved regarding to management of MMA/PA. LT patients do survive with less admission length, less tube feeding, less anxiety from caregiver; nevertheless, their DQ/IQ performance still necessitates further monitor.
Keywords: Methylmalonic acidemia (MMA); propionic acidemia (PA); liver transplantation (LT); newborns
