ABSTRACT
Biotinidase deficiency (BD) is an inborn metabolic disorder caused by low enzyme activity giving rise to impaired biotin release from dietary proteins. The first symptoms may be seen at first week following birth until 1 year of age. The goal of the therapy is to increase biotin bioavailability by daily 5-20 mg lifelong biotin replacement. Three-month-old girl born to nonconsanguineous parents, admitted to pediatric intensive care with multiple seizures, breathing difficulty and posturing. Blood investigations showed thrombocytopenia and high anion gap metabolic acidosis (HAGMA). Enzyme assay for biotinidase revealed low activities. Urinary organic acid analysis was normal. Enzyme activity is <10% in severe cases whereas between 10-30% in partial deficiency. BD can cause metabolic ketoacidosis, Hyperammonemia and organic Aciduria. BD behaves like immunodeficiency. Rarely bacterial infection can be seen. Treatment is lifelong biotin replacement.
ABSTRACT
OBJECTIVES: Urine anion gap(UAG) and urine osmolal gap(UOG) were proposed as indirect measures of urine ammonium(NF4+). While the former is known to have its usefulness limited to hyperchloremic metabolic acidosis, the latter is reported to have its correlation with urine NE4+ in ketoacidosis. This study was undertaken to evaluate the correlation of urine NH with IJOG in high anion gap metabolic acidosis(AGMA) and to compare it with UAG. METHODS: We measured urine NH' by enzymatic determination, UOG(=0.5 X [urine osmolality-{2 X (Na++K+)+urea+glucose)]), and UAG(=Na++K+-Cl-) in 18 patients(serum AG=24.4+/-1.6mmol/L ) with AGMA. RESULTS: When they were grouped into those with acute disorders(n=11) and those with chronic disorder(n=7), urine Nk4+ concentration was higher (p40mmol/d) had the UOG>40mmol/L. CONCLUSION: In contrast to the UAG, the UOG has a significant correlation with urine NH4+ in AGMA.