Determination of hexosamines in urine by HPLC for diagnosis of mucopolysaccharidoses type III

Abstract

In the present work a reported analytical method was optimized in order to improve the diagnostic of a rare disease: Mucopolysaccharidoses type III (MPS III). This process is based on the separation and quantification of hexosamines (glucosamine and galactosamine), released as products of glycosaminoglycans (GAGs) hydrolysis presents in urine, by HPLC and detected by fluorescence measures. The concentration of galactosamine and glucosamine in urine of 20 persons as control sample and 9 patients with MPS III was determined. The control group showed similar concentrations of both hexosamines in urine, whereas in the group of MPS III patients the concentration of glucosamine was significantly higher than galactosamine. According to the obtained data, it was demonstrated that the ratio of concentrations galactosamine/glucosamine is the most useful parameter to discern people affected by MPS III, being a normal ratio 0.91±0.08 and 0.28±0.03 the ratio to diagnose the disease. It was established a unique reference interval to control sample for every considered biochemical parameter. According to the procedure, GAGs were hydrolyzed with HCl and the released hexosamines were derivatized with anthranilic acid. Finally, different products were separated and quantified by reverse phase HPLC and with fluorescence detector.