Objective: The study is a retrospective review which provides preliminary data on the correlation between biochemical profiles and initial clinical manifestation of patients diagnosed to have argininosuccinate synthetase deficiency (ASSD) and argininosuccinate lyase deficiency (ASLD) detected by expanded newborn screening (ENBS). Methods: This is a study of five distal UCD patients initially detected by elevated citrulline on ENBS. Medical charts of the patients were reviewed. The initial clinical manifestations of the patients were correlated with results of biochemical tests. Results: There were four cases of ASLD and one case of ASSD reviewed in this study. All cases of ASLD were confirmed by the presence of argininosuccinic acid (ASA) in the urine metabolic screen (UMS). The plasma citrulline level of the ASSD patient is significantly elevated as compared to the ASLD patients (2,690 µmol/L; NV: 10-45 µmol/L). The ASSD patient and one ASLD patient were symptomatic within the first six days of life. Both presented with significantly elevated plasma ammonia, citrulline and glutamine levels. Three ASLD patients were asymptomatic on initial screening. Conclusion ENBS has shown importance in the early detection and management of ASSD and ASLD. Early initiation of management may prevent hyperammonemic crises. Long term outcome studies are needed to look into the correlation of neurodevelopmental outcome with lifelong accumulation of citrulline and glutamine in ASSD and ASA in ASLD.
Citrullinemia ; Argininosuccinic Aciduria ; Argininosuccinic Acid

Argininosuccinic aciduria is an inborn error of the urea cycle caused by deficiency of argininosuccinate lyase (ASL). ASL-deficient patients present with progressive intoxication due to accumulation of ammonia in the body. Early diagnosis and treatment of hyperammonemia are necessary to improve survival and prevent long-term handicap. Two clinical phenotypes have been recognized--neonatal acute and milder late-onset form. We investigated patients with hyperammonemia by a stepwise approach in which quantitative amino acids analysis was the core diagnostic procedure. Here, we describe the clinical phenotypes and biochemical characteristics in diagnosing this group of patients. We have identified 13 patients with argininosuccinic aciduria from 2003 till 2009. Ten patients who presented with acute neonatal hyperammonemic encephalopathy had markedly elevated blood ammonia (> 430 micromol/L) within the first few days of life. Three patients with late-onset disease had more subtle clinical presentations and they developed hyperammonemia only during the acute catabolic state at two to twelve months of age. Their blood ammonia was mild to moderately elevated (> 75-265 micromol/L). The diagnosis was confirmed by detection of excessive levels of argininosuccinate in the urine and/or plasma. They also have moderately increased levels of citrulline and, low levels of arginine and ornithine in their plasma. Two patients succumbed to the disease. To date, eleven patients remained well on a dietary protein restriction, oral ammonia scavenging drugs and arginine supplementation. The majority of them have a reasonable good neurological outcome.
Age of Onset ; Amino Acids/analysis ; Argininosuccinic Acid/blood ; Argininosuccinic Acid/urine ; Argininosuccinic Aciduria/*diagnosis ; Argininosuccinic Aciduria/*metabolism ; Argininosuccinic Aciduria/*physiopathology ; Malaysia ; Phenotype

Citrullinemia is a rare inborn error of metabolism of the urea cycle, and was first reported by McMurray, et al. in 1962. It is inherited as an autosomal recessive trait. The normal synthesis of argininosuccinic acid is blocked in this disease due to a deficiency of argininosuccinic acid synthetase(AS), which has been demonstrated in liver cells and fibroblasts. The clinical symptoms are vomiting, lethargy or irritability, convulsion and mental retardation. The diagnosis is made by the finding of an increased plasma citrulline level. Every effort should be made to reduce the blood ammonia level as rapidly as possible before irreversible brain damage occurs. This report describes a case of citrullinemia that was diagnosed through organic acid analysis and amino acid analysis, and reviews the related literatures.
Ammonia ; Argininosuccinic Acid ; Brain ; Citrulline ; Citrullinemia* ; Diagnosis ; Fibroblasts ; Intellectual Disability ; Lethargy ; Liver ; Metabolism ; Plasma ; Seizures ; Urea ; Vomiting

Citrullinemia is one of the five urea cycle defects and is caused by argininosuccinic acid synthetase deficiency ; conversion of citrulline to argininosuccinic acid is blocked. Severe hyperammonemia typically develops in the neonate within a few days and symptoms such as vomiting, lethargy, convulsion, coma follows rapidly. The diagnosis is supported by high citrulline level in serum, urine, CSF and decreased activity of argininosuccinic acid synthetase in liver biopsy. We experienced a 3-day-old male neonate with poor activity, lethargy, convulsion, and coma who was diagnosed as citrullinemia by markedly elevated plasma and urine citrulline level with hyperammonemia. We report this case with brief review of the related literature.
Argininosuccinic Acid ; Biopsy ; Citrulline ; Citrullinemia* ; Coma ; Diagnosis ; Humans ; Hyperammonemia ; Infant, Newborn ; Lethargy ; Ligases ; Liver ; Male ; Plasma ; Seizures ; Urea ; Vomiting

Citrullinemia is one of the five urea cycle defects and is caused by argininosuccinic acid synthetase deficiency ; conversion of citrulline to argininosuccinic acid is blocked. Severe hyperammonemia typically develops in the neonate within a few days and symptoms such as vomiting, lethargy, convulsion, coma follows rapidly. The diagnosis is supported by high citrulline level in serum, urine, CSF and decreased activity of argininosuccinic acid synthetase in liver biopsy. We experienced a 3-day-old male neonate with poor activity, lethargy, convulsion, and coma who was diagnosed as citrullinemia by markedly elevated plasma and urine citrulline level with hyperammonemia. We report this case with brief review of the related literature.
Argininosuccinic Acid ; Biopsy ; Citrulline ; Citrullinemia* ; Coma ; Diagnosis ; Humans ; Hyperammonemia ; Infant, Newborn ; Lethargy ; Ligases ; Liver ; Male ; Plasma ; Seizures ; Urea ; Vomiting