Mucopolysaccharidosis Type II (MPS II), also known as Hunter syndrome, is a lysosomal storage disorder (LSD) caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS). MPS II satisfies all criteria defined by the Advisory Committee on Heritable Disorders in Newborns and Children (ACHDNC) for inclusion in the Recommended Uniform Screening Panel (RUSP) for newborn screening, apart from the fact that only minimal prospective population screening data are available.
This report details the analytical validation, clinical validation, and implementation of a fluorometric assay for measurement of IDS activity in newborn dried blood spot (DBS) specimens at the Missouri State Public Health Laboratory (MSPHL).
Following validation, MSPHL began prospective screening using the IDS assay on 1 November 2018. In the first 18 months of screening (to 30 June 2020), 146,954 specimens were prospectively screened using the method. Two newborns were identified with severe Hunter syndrome and the assay had a presumptive positive rate of 0.022%.
Authors: Heather Bilyeu, Jon Washburn, Lacey Vermette, Tracy Klug
International Journal of Neonatal Screening. 2020, 6(4), 70; https://doi.org/10.3390/ijns6040078