Definition:
MPS IX (Hyaluronidase deficiency) is a condition that was first noted in 1996. It is caused by a deficiency of the enzyme, hyaluronidase. This enzyme is used in the lysosome to break down a complex string of sugars known as Glycosaminoglycans (GAGs), often referred to as mucopolysaccharides. In individuals inflicted with MPS IX , the GAG accumulates resulting in symptoms of this disorder. In this disorder, the accumulation of these sugars primarily affects the joints.

To date, there has been one reported case of MPS IX.

Symptoms:
Symptoms include nodular soft-tissue masses located around joints, with periodic episodes of painful swelling of the masses . This pain spontaneously ends within three days.

Other symptoms of this disease include a flattened nose bridge and a cleft palate. Short stature is also a noted symptom. Intelligence has not been noted in MPS IX.

Inheritance Patterns:
MPS IX is an autosomal recessive disorder.

Life Expectancy:
Given the rare occurrence of this disorder, life expectancy is not known at this time.

Diagnosis and Testing:
An enzyme assay, which measures the amount of the enzyme, hyaluronidase in cultured tissue cells, confirms a diagnosis of MPS IX. Individuals affected by MPS IX would have very low amounts of this enzyme in their cells.

Pelvic radiography can identify soft-tissue masses and bone erosion. Recently, the mutated gene and its corresponding chromosome have been identified.

Treatment:
Since there has been only one reported case of MPS IX, and the individual had a very mild type of this disorder, very few treatments have been developed. Regular radiography scans are recommended to measure the presence of soft-tissue masses and of bone erosion.

Patient Groups:
National MPS Society
4220 NC Highway 55, Suite 140
Durham NC, 27713
www.mpssociety.org
tel: (919) 806-0101
fax: (919) 806-2005
Barbara Wedehase, Executive Director
info@mpssociety.org