Hurler Syndrome, Hurler-Scheie Syndrome, and Scheie Syndrome (Mucopolysaccharidosis Type I) Workup

Updated: Sep 28, 2018
  • Author: Germaine L Defendi, MD, MS, FAAP; Chief Editor: Maria Descartes, MD  more...
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Workup

Laboratory Studies

Alpha-L-iduronidase activity is less than 1% in all forms of mucopolysaccharidosis type I (MPS I). The following studies are indicated in patients with suspected MPS I:

  • Lymphocytes in the blood smears may be examined for abnormal cytoplasmic inclusions.
  • Urinary testing to detect levels of the mucopolysaccharides dermatan sulfate (DS) and heparan sulfate (HS)
  • Levels of alpha-L-iduronidase, present in lysosomes, may be assayed in cultured fibroblasts and in leukocytes. [6]
  • Prenatal diagnosis to detect alpha-L-iduronidase can be performed on amniotic cells and chorionic villi cells.
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Imaging Studies

Echocardiography is useful to diagnose cardiac abnormalities.

In severe MPS I, skeletal radiography (especially of the spine) can be used to detect a gibbus deformity of the lower spine.

Dysostosis multiplex (a specific pattern of radiographic changes observed in many lysosomal storage disorders) can be seen on radiographs. See the images below.

Hurler syndrome; lateral radiograph of thoracolumb Hurler syndrome; lateral radiograph of thoracolumbar vertebrae illustrates vertebral plana. Courtesy of Bruce M. Rothschild, MD.
Hurler syndrome; widened metaphyses and diaphyses Hurler syndrome; widened metaphyses and diaphyses with truncated distal portions forming a peg characterize this radiograph. Courtesy of Bruce M. Rothschild, MD.
Hurler syndrome; widened metaphyses and diaphyses Hurler syndrome; widened metaphyses and diaphyses with truncated distal portions forming a peg characterize this radiograph. Courtesy of Bruce M. Rothschild, MD.
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Other Tests

Visual and auditory impairments require ocular and otic evaluations in patients with MPS I and attenuated MPS I.

Guidelines for hearing assessments in infants and children have been established by the American Academy of Pediatrics. [7]

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