- Discussion:
- are characterized by a defect in metabolism of one or more mucopolysaccharides, w/ resulting
excessive accumulation of these substances in the extracellular spaces of the connective tissues;
- this group of disorders is characterized by a deficiency of specific lysosomal enzymes
required for degradation of
glycosaminoglycans;
- substances accumulate in tissues such as brain, viscera, heart, lung, and joints;
- clinical features:
- coarse facial features
- short stature
- platyspondyly with an anterior tongue
- broad medial end of the clavicle
- characteristic pelvis with flared iliac wings
- large capacious acetabula
- unossified femoral head cartilage with coxa valga;
- Specific Disorders:
-
Morquio's syndrome;
-
Hurler-Scheie:
- most severe mucopolysaccharide storage disorder which causes cardiopulmonary complications and results
in death within first decade of life;
- patients are usually diagnosed between the ages of 1-3 years;
- enzyme defect may be detected in the blood and on skin bx, which allows accurate dx, carrier detection, and prenatal dx;
- course facial features (thickened lips, widened nostrils, large ears) and hepatosplenomegaly are seen be 18 months of age;
- other characteristics include:
- short stature, w/ disproportionately short trunk, thoracolumbar kyphosis (anterior-inferior vertebral beaking);
- elbow, hip, and knee flexion contractures;
- atlantoaxial instability has now been demonstrated & screening for instability is now suggested;
- corneal opacities;
- labs: increased urine heparin and dermatin sulfate;
-
Hunter:
- sex linked recessive disorder which is also characterized by increased heparin and dermatin sulfate;
- usually clear cornea
- mild course: later manifestation and survival into adulthood w/ or without mental retardation;
-
San Filippo's syndrome:
- presents in early childhood and progresses in severity;
- may be confused with
cerebral palsy because patients have hyper-reflexia and spasticity, however, unlike
cerebral palsy, this disorder progresses in severity;
- patients have the course facial features seen in other mucopolysaccharidoses;
- urine is positive for heparin sulfate;
Hurler syndrome with special reference to histologic abnormalities of the growth plate.
Musculoskeletal manifestations of hurler syndrome: long-term follow-up after bone marrow transplantation.
Cord-Blood Transplants from Unrelated Donors in Patients with Hurler's Syndrome.
