The Critical Role of Fractionated Urine Glycosaminoglycans in the Evaluation of Mucopolysaccharidosis Type II in Four Unrelated Families.
Carly A Rasmussen, Monika Izdebski, Allison Paltzer et al.
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Case in brief
The report describes infants from four unrelated families who screened positive for mucopolysaccharidosis type II (MPS II) on the Illinois newborn screen. Initial evaluation included plasma iduronate-2-sulfatase activity, urinary glycosaminoglycan analysis, and IDS gene sequencing. Although these tests usually ruled out or confirmed MPS II, in some cases the diagnosis remained uncertain. The authors describe using fractionated urinary glycosaminoglycan analysis as part of their approach to resolving these indeterminate evaluations and confirming or excluding MPS II.
What made this case unusual
The diagnostic challenge was persistent uncertainty after the usual enzyme, urinary glycosaminoglycan, and genetic studies; fractionated urinary glycosaminoglycan analysis was highlighted as useful in these cases.
Diagnostic / clinical pearl
When initial biochemical and IDS sequencing results do not settle suspected MPS II after a positive newborn screen, fractionated urinary glycosaminoglycan analysis can help clarify the diagnosis.