- Uploaded
- 22 Jul 2008
|
|
- "Type II: In these people, the von
Willebrand factor itself has an abnormality. Depending on the abnormality, they
may be classified as having Type IIA or Type IIB. In Type IIA, the level of von
Willebrand factor is reduced as is the ability of platelets to clump together.
In Type IIB, although the factor itself is defective, the ability of platelets
to clump together is actually increased."
http://www.haemophilia.org.za/Vonwil2.htm
- "Type 2: There are four main categories of
type 2 used in the classification of vWD, although more than 50 distinctive
defects in the vWF molecule have been identified. About 20% of patients with vWD
have type 2A or 2B, which results from a qualitative deficiency of vWF. In other
words, their vWF protein is structurally and functionally abnormal. Unlike in
type 1, individuals with type 2 vWD produce normal levels of vWF, but that vWF
is dysfunctional. Type 2 disease severity can vary from individual to individual
and can also fluctuate in the same patient over time. In type 2 vWD, the
multimers, or building blocks, of vWF are impaired, and this results in
variations of the expression of the disease. Type 2A vWD is characterized by a
decrease in platelet-dependent function, with a loss of high-molecular-weight
multimers. Type 2B results in an increased affinity of the vWF for the platelet
membrane glycoprotein 1b-IX complex, resulting in the removal of platelets and
vWF from the blood."
http://www.uspharmacist.com/NewLook/Ce/von/lesson.cfm
-
|