Sly Syndrome (Mucopolysaccharidosis Type VII) Workup

Updated: Jan 18, 2023
  • Author: Germaine L Defendi, MD, MS, FAAP; Chief Editor: Maria Descartes, MD  more...
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Laboratory Studies

Disease-specific tests

Granulocytes studies reveal the presence of coarse metachromatic inclusions in patients with Sly syndrome (mucopolysaccharidosis type VII [MPS VII]).

Mucopolysacchariduria or increased levels of urinary glycosaminoglycan (either chondroitin sulfate [CS] alone or dermatan sulfate [DS], heparan sulfate [HS], and CS combined) is observed.

Diagnosis is confirmed by demonstration of beta-glucuronidase deficiency in cultured leukocytes or fibroblasts. Pseudodeficient alleles make mild forms more difficult to identify and make prenatal diagnosis difficult.

Molecular analysis of the GUSB gene may be performed.

Prenatal diagnosis

Prenatal diagnosis of beta-glucuronidase deficiency also may be offered to expectant couples with a history of a previously affected child, using the following methods:

  • Enzyme assay of amniotic fluid
  • Molecular analysis amniotic cells and chorionic villi cells

Imaging Studies

Skeletal features of Sly syndrome become evident in the first few years of life. In many patients, radiographic studies may reveal J-shaped sella turcica, odontoid hypoplasia, dysostosis multiplex, acetabular hypoplasia (dislocated hips), platyspondyly (flattening of the vertebral bodies), and thoracolumbar kyphoscoliosis. [8]