Test Identifies Early Signs of Mucopolyscaccharidoses

A team of scientists have developed a simple, reliable test for identifying biomarkers for mucopolysaccharidoses (MPS), a group of inherited metabolic disorders that are currently diagnosed in patients only after symptoms have become serious and the damage possibly irreversible.

The scientists developed an innovative method to detect carbohydrate structures specific to glycosaminoglycans in the cells, blood, and urine of MPS patients. The biomarker assay identifies all known forms of the disease.

The effects of MPS range from mild to severe. It is caused by the absence or malfunctioning of a lysosomal enzyme required to break down and recycle complex sugar molecules called glycosaminoglycans, which are used to build bone, tendons, skin, and other tissues. If not degraded and removed, glycosaminoglycans can accumulate in cells and tissues, resulting in progressive, permanent damage affecting appearance, physical abilities, organ function, and often mental development in young children.

There are 11 known forms of MPS, each involving a different lysosomal enzyme. A number of treatments exist, including enzyme replacement therapy and hematopoietic stem cell transplantation, but efficacy depends upon diagnosing the disease and its specific form as early as possible.

That has been problematic, said Jeffrey D. Esko, PhD, professor in the Department of Cellular and Molecular Medicine and codirector of the Glycobiology Research and Training Center at University of California (San Diego, CA, USA).

"The typical time from seeing first symptoms to diagnosis of MPS is about three years. Since the early signs of disease are common childhood issues like ear infections and learning disorders, the disease is usually not immediately recognized," Prof. Esko said.

Prof. Esko is collaborating with Zacharon Pharmaceuticals (San Diego, CA, USA), a biotechnology company, to develop a commercial diagnostic assay for differentiating forms of MPS from urine and blood samples, a screening test for newborns, and a tool for measuring the biochemical response of MPS patients to existing and novel therapies.

The findings were published online January 8, 2012, in the journal Nature Chemical Biology.

Related Links:
University of California, Department of Cellular and Molecular Medicine
Zacharon Pharmaceuticals