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MSU College of Osteopathic Medicine

I. Introductory concepts

A. Clinical Expression

The neurological complications of these disorders range from specific focal abnormalities to mental retardation. The precise reason for the mental retardation is not clear. There is marked variation in the age of onset, rate of progression and organ and skeletal involvement among disorders and among variants of each disorder.  This is due to factors such as the different isoenyzmes involved, solubility of accumulated products for excretion and the specific biochemical reactions occurring in various organs. In general earlier age of onset is associated with a more severe clinical course. The only disorders described below are the early onset forms of a few selected examples.

 B. Inheritance Pattern

Almost all of these disorders are characterized by autosomal recessive transmission

 C. Mechanisms of Damage

Functional and pathological damage may be produced by loss of end product of a reaction due to enzyme deficiency, accumulation of substances prior to the metabolic block, or production of toxic metabolites.  Almost certainly, indirect effects are also exerted on other metabolic pathways or functional elements.