AB031. Spectrum of IEMs in Vietnamese patients: data from 10 years of selected screening and diagnosis
Vu Chi Dung1, Nguyễn Ngọc Khánh1, Nguyen Chi Mai1, Bùi Thị Hương1, Bui Phuong Thao1, Can Thi Bich Ngoc1, Nguyen Thi Hoan1, Le Thanh Hai1, Khu Thi Khanh Dung1, Toshiyuki Fukao2, Seiji Yamaguchi3
Background and objective: Vietnam is the easternmost country on the Indochina Peninsula in Southeast Asia. With an estimated 90 million inhabitants as of 2013, it is the world’s 13th-most-populous country, and the eighth-most-populous Asian country. Congenital anomalies accounted about 22% of causes of deaths in children under-5 [2010]. The first service for IEMs was set up at the Northern referral center of Pediatrics-National Hospital of Pediatrics, Hanoi (NHP) in 2004 officially. The NHP in Hanoi provides services to the population of North Vietnam (~30 million people). The aim of this report is to highlight disease spectrum of tandem mass spectrometry (MS/MS) target disease in Vietnam.
Methods: A total of 2,405 high-risk cases with IEMs were studied at NHP during 10 years [2005-2014]. Dry blood and urine samples were analyzed using MS/MS (amino acid & acylcarnitine analysis) & GC/MS (organic acid anaysis) at Shimane University, Japan from 2005. Organic acids analysis for fresh urine samples was performed at NHP using GC/MS at NHP from 2010. Amino acid analysis for plasma samples were performed using HPLC at NHP from 2012.
Results: Oganic acidemia (OAs), amino acid disorders (AAs), urea cycle disorders (UCDs) and fatty acid oxidation disorders (FAOD) were identified in 235/2,405 cases (9.8%). A total of 118/235 patients (50.2%) were OAs with 12 different disorders: BKT (33 cases), PPA (21 cases), 5-oxoprolinuria (19 cases), MMA (14 cases), Glutaricaciduria type II (GA II) (11 cases), 3-methylglutaconic aciduria (4 cases), isovaleric academia (3 cases), multiple carboxylase deficiency (MCD) (2 cases), 3-methylcrotonylCoA carboxylase deficiency (2 cases). A total of 42/235 patients (17.9%) were amino acid disorders including 35 cases with MSUD, 7 cases with PKU and 1 case with tyrosinemia type 1. The 36/235 patients (15.3%) were UCDs including OTC deficiency (13 cases), citrulinemia type 1 (1 case) and argininosuccinic aciduria (1 case). 39/235 patients (16.6%) were FAOD including SCAD (3 cases), MCAD (3 cases), VLCAD (8 cases), LCAD (2 cases), CPT 2 (8 cases), CPT 1 (1 case) and primary carnitine deficiency (14 cases). Mortality rate was reduced from 50% in 2005 to 9% in 2014.
Conclusions: Treatable conditions of IEMs were most common in Vietnamese patient identified using MS/MS. Expending newborn screening using MS/MS should be introduced to reduce mortality in Vietnamese children.
Keywords: Tandem mass spectrometry (MS/MS); inborn errors of metabolism (IEMs); newborn screening; Vietnam
