ABSTRACT
Fresh urine sample is required for measurement of pterins in patients with hyperphenylalaninemia (HPA) for detection of tetrahydrobiopterin (BH4) coenzyme deficiency. The present study aimed to measure the levels of neopterin and biopterin in the urine of patients with HPA using manganese dioxide (MnO2) and iodine oxidation methods. The levels of neopterin and biopterin in the urine of 124 patients were measured using two methods of oxidation (MnO2 and iodine) and the results were statistically analyzed using correlation test, Roc-Curve and ANOVA in SPSS-20 software. The level of significant was determined to be P > 0.05. Patients age mean ± SD = 4.96 year, neopterin and biopterin mean ± SD in 124 patients were 2.75 mmol/molcr and 2.49 mmol/molcr. Correlation regression between two methods (iodine and MnO2 oxidation) was 0.99. There was no significant difference between the two oxidation methods (P > 0.05). The results of this study showed that MnO2 oxidation can be a suitable alternative method instead of iodine oxidation for measurement of urine neopterin, biopterin and diagnosis of BH4 deficiency.
ABSTRACT
BACKGROUND: Biotinidase deficiency (BTD) is an autosomal recessive disorder of biotin metabolism. Biotin is a coenzyme that enhances the action of the four enzymes that play an important role in carbohydrates, amino acid, and fatty acid metabolism. Defects in these pathways cause severe metabolic disorder in the body. In general, biotinidase deficiency can be classified into two levels: partial and profound. The incidence of BTD is 1:40,000 to 1:60,000 births in the world, even though no convincing statistical data on the prevalence of this disorder exist in Iran. In this study, we aimed to set up a test for determining biotinidase activity among the Iranian population and report BTD mutations. PATIENTS AND METHODS: The quantitative method for the determination of biotinidase activity was set up in the National Biochemistry Reference Laboratory (NBRL) of Pasteur Institute of Iran in Tehran. To detect mutations in BTD, polymerase chain reaction (PCR) was performed followed by DNA sequencing. RESULTS: The biotinidase activity range values were 3.81 - 8.25 nmol/min/mL. We identified 8 BTD patients out of 47 cases with neurologic signs. We detected two mutations, c.98-104del7ins3 and p.Arg79Cys, in 5 patients with profound BTD, and one p.Asp444His mutation in 3 patients with partial BTD. CONCLUSION: Infants suffering from BTD seem healthy during their first months of life. At present, the screening program for metabolic disorders such as BTD is in progress. The patients that are BTD deficient benefit from the availability of the tests, and consequently receive the Biotin supplements before being clinically affected.
