Maroteaux-Lamy Syndrome (Mucopolysaccharidosis Type VI) Workup

Updated: Mar 20, 2017
  • Author: Paul R Harmatz, MD; Chief Editor: Maria Descartes, MD  more...
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Workup

Laboratory Studies

Urine glycosaminoglycan analysis can be performed using various qualitative or quantitative methods. These studies are useful for establishing the likely diagnosis of mucopolysaccharidosis (MPS) but do not provide a specific diagnosis, which requires enzymatic testing.

Definitive diagnosis requires the determination of the specific lysosomal enzyme level in cultured fibroblasts or isolated leukocytes.

Normal levels of a second sulfatase should be documented to exclude multiple sulfatase deficiency.

Mutational analysis of the ARSB gene should be considered if the diagnosis is in question. [8, 9]

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Imaging Studies

Perform skeletal survey studies to reveal dysostosis multiplex. Findings may include the following:

  • Macrocephaly with an enlarged j-shaped sella

  • Thickened, short metacarpal bones with proximal pointing and thin cortices

  • Paddle-shaped, widened ribs

  • Short, thick irregular clavicles

  • Dysplastic femoral head

  • Severe hip dysplasia

  • Ovoid deformities of the vertebrae

  • Anterior hypoplasia of the L1 and L2 vertebral bodies

  • Evidence of kyphoscoliosis

Echocardiography can reveal valvular heart disease, which is common. Acute infantile cardiomyopathy has also been reported in mucopolysaccharidosis type VI (MPS VI), also known as Maroteaux-Lamy syndrome.

MRI of the brain and spine may demonstrate hydrocephalus or provide evidence for spinal cord compression and spinal cord malacia, especially in the cervical region.

Flexion-extension radiography of the C-spine may demonstrate atlantoaxial instability and subluxation of C1 on C2; CT scanning may be necessary if radiograph images are not clearly interpretable.

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Other Tests

Perform an audiological evaluation because deafness and hearing loss are common in MPS.

Perform an ophthalmologic examination to identify corneal opacities, vision change, and optic nerve abnormalities, suggesting increased intracranial pressure.

Perform pulmonary function tests to monitor restrictive and obstructive disease and perform a sleep study to evaluate for sleep apnea.

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Histologic Findings

Lysosomal engorgement in tissue biopsies is evident, as are vacuolated lymphocytes on peripheral blood smear.

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Staging

Urine glycosaminoglycan (GAG) level corrected for creatinine is a biochemical disease marker that can provide a crude estimate of disease severity and response to specific treatment (hematopoietic stem cell transplant [HSCT ] or enzyme replacement therapy).

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