Abstract
Objective: The urea cycle is a pathway by which urea is produced from ammonia primarily in the liver. Urea cycle disorders are inborn errors of this metabolic pathway. Decreased excretion of nitrogen in the urea cycle due to deficiencies of carbamoylphosphate synthase (CPS-I), ornithine transcarbamylase (OTC), argininosuccinate synthase (ASS), argininosuccinate lyase (ASL), arginase (ARG) and N-acetylglutamate synthase (NAGS) causes hyperammonemia. Frequently seen sign and symptoms are nausea-vomiting, loss of appetite, failure to thrive, hyperammonemia, liver failure, fatty liver, hepatomegaly, convulsions, stupor, coma and mental-motor retardation.
Material and Methods: In this study, the clinical data, mutations, and prognosis of 20 patients with UCD from the south part of Turkey were evaluated retrospectively.
Results: 20 patients (12F/8M) from 17 families were enrolled in the study. Symptoms were poor feeding, neurological problems, and nausea-vomiting. Most of the parents (15/17) were consanguineous. The family history rate was 8/17. The median age of symptoms was three days (0 days-3 years). Twelve patients presenting in the neonatal period had hyperammonemia. Nine patients had citrullinemia, six arginase deficiency, two CPS-I deficiency, one OTC deficiency, one ASL deficiency, and one NAGS deficiency. Genetic analyses of the patients revealed eight novel mutations out of the 14 different mutations. Five patients died during an acute metabolic crisis.
Conclusion: OTC deficiency is the most common form in the literature but we observed a higher percentage of citrullinemia type 1 than reported in the literature among urea cycle disorders. Genetic heterogeneity was observed in a screened cohort in spite of the high rate of consanguineous marriages in Turkey, which is considered to be an important factor contributing to the higher incidences of autosomal recessive hereditary diseases. Eight new mutations were also added to the genotypic spectrum of the disorder with the current analysis.
Keywords: Hiperamonemi, Mutasyon
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Copyright and license
Copyright © 2020 The Author(s). This is an open access article distributed under the Creative Commons Attribution License (CC BY), which permits unrestricted use, distribution, and reproduction in any medium or format, provided the original work is properly cited.
