AB103. Phenotype and genotype of urea cycle defect in a Vietnamese referral center
Part 4: Oral/poster

AB103. Phenotype and genotype of urea cycle defect in a Vietnamese referral center

Khanh Ngoc Nguyen1, Huong Thi Bui1, Dung Chi Vu1, Ngoc Thi Bich Can1, Thao Phuong Bui1, Mai Chi Nguyen1, Hung Viet Daut1, Tuan Anh Dang1, Seiji Yamaguchi2, Gu-Hwan Kim3, Han Wook Yoo3

1National Hospital of Paediatrics, Hanoi, Vietnam; 2Shimane University School of Medicine, Shimane, Japan; 3Medical Genetics Center, Asan Medical Center, Seoul, Korea

Background and objective: Urea cycle disorders (UCDs) are inborn errors of ammonia detoxification/arginine synthesis due to defects affecting the catalysts of the Krebs-Henseleit cycle. Clinical spectrum of UCDs is variant from mild to severe form. To describe clinical spectrum and genotype of UCDs in Vietnamese patients.

Methods: Case series report of 20 patients with UCDs from 2005 to 2014 at National Hospital of Pediatrics, Hanoi, Vietnam.

Results: During 10 years, we have 20 cases with UCDs including 2 case of argininosuccinic ciduria; 6 cases of citrullinemia type 1; 12 cases with ornithine transcarbamylase deficiency (OTC). Ten cases (two with argininosuccinic aciduria, five cases with citrullinemia type 1 and three cases with OTC) were newborn onset form. The remaining 10 cases were late onset form. All of newborn onset patients presented with poor feeding, irritability, then coma and dyspnea with hyperammonemia (415-1,254 µg/dL). Clinical symptoms of late onset patients were variant: acute encephalopathy (6/10), recurrent vomiting (5/10), convulsion (4/10), development delay (4/10), hemiplegia (3/10), elevated transaminase (10/10), coagulation disorders (10/10), hyperammonemia (200-1,200 µg/dL) with onset age from 4 to 18 months. Only one case of newborn onset form is survival with normal development (OTC deficiency—20 months old boy), 9/10 cases of late onset form is survival with normal development and mild development delay. Mutation Analysis was identified three causative hemizygote mutations c.77G > A (p.R26Q), c.298+5G>C (IVS3+5G > C) and c.422G > A (p.R141Q) of OTC in three probands and a nonsense homozygous mutation in exon 14 c.1030C > T (p.R344X) of ASS gene in one proband.

Conclusions: UCDs can occur at any age with non-specific neurological, hepatic—gastrointestinal, psychiatric symptoms. UCDs had good prognosis if early diagnosis and adequate management

Keywords: Urea cycle disorder (UCD); ornithine transcarbamylase deficiency (OTC); Citrullinemia type 1; argininosuccinic aciduria

Cite this abstract as: Nguyen KN, Bui HT, Vu DC, Can NT, Bui TP, Nguyen MC, Daut HV, Dang TA, Yamaguchi S, Kim GH, Yoo HW. Phenotype and genotype of urea cycle defect in a Vietnamese referral center. Ann Transl Med 2015;3(S2):AB103. doi: 10.3978/j.issn.2305-5839.2015.AB103

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