High-throughput determination of urinary hexosamines in newborns of 2-3 days of age: application for the early diagnosis of mucopolysaccharidoses

Backgroung In this study, we propose a high-throughput procedure for the simultaneous determination of glucosamine and galactosamine generated from urinary glycosaminoglycans (GAGs) applied to healthy newborns of 2-3 days of age. Methods The GAGs of urine of 155 healthy newborns having 2-3 days of age were rapidly treated with HCl after precipitation with ethanol. Generated hexosamines were separated by HPLC equipped with a fluorimetric detector after derivatization with a fluorescence molecule. Results Both hexosamines, galactosamine (GalN) and glucosamine (GlcN) were rapidly and clearly separated and quantified obtaining a GalN/GlcN ratio of 0.74 with a CV% of ~29%. By comparing these new data obtained on the urine of newborns of 2-3 days of age with those previously published [Coppa GV et al. Anal. Biochem. 411, 32, 2011], we obtained significant differences of GalN/GlcN ratio in patients affected by MPS I, II, III and VI. Subjects with MPS IV were found borderline and further studies are necessary. No significant differences were observed with 83 heathy subjects of ~4 years old. Discussion Contrary to other analytical approaches, the present procedure is able to measure total abnormal amounts of urinary GAGs, high-molecular mass and related fragments, as well as specific hexosamines belonging to a group of GAGs. We propose this assay for possible application in MPS early diagnosis. In fact, due to the high-throughput nature of this approach and to the equipment commonly available in laboratories, this method may be suitable for newborn screening in preventive public health programs for early detection of MPS disorders, diagnosis and treatment