Handbook of Genetic Counseling/Scheie Syndrome

Scheie Syndrome

Introductions

Definition: It is a mucopolysaccharidoses Type I disease. This means the body has trouble breaking down the large molecules in the lysosomes. Instead of breaking them down completely, they kick out only partially degraded molecules = storage occurs as well. So there is an increase of stuff in the lysosomes causing a build up in various parts of the body
Incidence
- 1/500,000 births
Characteristics
- Broad mouth and fill lips
- Clouding of corneas/visual impairment
- Aortic valve defects
- Hairy body
- Hernias are common
- Carpal tunnel syndrome
- Joint limitation leading to claw hand.
- Normal life span
Genetics
- Autosomal recessive
- Chromosome 4p16 has a defect = the alph-L-iduronidase gene

Bone marrow transplants -experimental
Fetal tissue transplants - experimental
Enzyme replacement - experimental (When lysosomal storage diseases were discovered, hopes were raised that they could be treated by enzyme substitution. When exogenous lysosomal enzymes are injected into the patient, this enzyme can eventually be taken up by enzyme-deficient cells. This uptake is regulated by certain receptors on the cell surface. Different tissue have different receptors. It is therefore necessary to change the natural enzyme to enable uptake in the tissue of interest. If properly designed, the missing enzyme could be injected regularly like the diabetic subject injects insulin. In many in vitro studies with the purified active enzyme added to the media of enzyme-deficient fibroblasts, the lysosomal substrate accumulation was corrected, but in vivo treatment has been hampered through the problem of producing the sufficient quantity of enzymes, immunological problems, and that the substituted enzyme does not pass the blood-brain barrier.
Since it can be expected that enzymes supplied from the outside do not pass the blood brain barrier, suitable candidates for enzyme replacement are disorders without neurological involvement (e.g. Maroteaux Lamy, Morquio B, Fabry, late onset Pompe disease).

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The information in this outline was last updated in 2000.