There are several known causes for Budd-Chiari syndrome ( occlusion of the hepatic veins )
thrombosis, pregnancy/contraceptive use, infections, congenital ...
http://en.wikipedia.org/wiki/Budd-Chiar ... ome#Causes
Jugular Vein Thrombosis is a condition that may occur due to infection, intravenous drug use or malignancy, ...
http://emedicine.medscape.com/article/1162804-overview
I believe interventional radiologists never proved CCSVI to be congenital,
they just classified it [somehow] in their Hamburg classification,
as in "we are aware of this condition, we will accept your money".
Vitamin D - high pathogenic load -> lower vit d ?
HIV: People living with HIV use more vitamin D for normal bodily processes than others do.
http://aids.about.com/od/nutrition/a/vitamin_d.htm
TB: Patients with active tuberculosis are more likely to be vitamin D deficient than the rest of the population
http://www.medicalnewstoday.com/articles/103480.php
MS: during an acute [MS] attack, the vitamin D levels go way down
http://www.thisisms.com/ftopicp-110878.html
Imho, CCSVI may be congenital for some people, some may have CCSVI because of some injury, thrombosis,
infection ( bacterial, viral, fungal, ... -> inflammation, venous stenosis ), ...