Glycoproteins diseases associated with abnormalities

Urinary casts, often excreted by patients having renal disease, possess414 antigenic determinants in common with the Tamm-Horsfall protein (see p. 414), and, indeed, this glycoprotein is the major component of the casts.414-416 However, the reason for its aggregation is as yet unknown. Other pathological states may well be found to be associated with abnormalities in the structure or metabolism, or both, of glycoproteins. 

Type 2 von Willebrand disease, diagnosed in 9% to 30% of affected patients, is characterized by a qualitative abnormality of von Willebrand factor. Bleeding manifestations may be more severe than with type 1 disease. Inheritance is most often autosomal dominant, but may be recessive. Type 2 von Willebrand disease may be further subdivided into four variants. Type 2A is the most frequent subtype and is characterized by a reduced von Willebrand factor-platelet interaction and an absence of high- and intermediate-molecular-weight factor multimers. Type 2B is a less common variant in which there is an abnormal von Willebrand factor that has an increased affinity for the platelet glycoprotein Ib receptor. This is associated with thrombocytopenia, which is usually mild. In addition, there are usually no high-molecular-weight forms of von Willebrand factor. Type 2M... 

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