The previous responder was correct. There are no real known causes except exposure to benzine and other petroleum based products and an acquired version from some chemotherapy regimens.
The majority of cases are ideopathic which means the cause is unknown. My specialist at M.D. Anderson hospital in Houston thinks the condition is viral in nature since all of her patients, including myself, despite their blood counts, constantly feel fatigued. In my case, it feels like you are coming down with the flu on a daily basis.
Treatments vary as do there effectiveness. You are generally classified as being severe or moderate. If any of your counts are in the severe stage then your condition is life threatening. My counts personally have flucuated. At present, I am symptom free with stable but slightly rising counts. I am on no medication at this point since I wasn’t getting any results. If you are researching AA on the web you have to be aware that you are going to be reading about the “worse” cases and it can be very depressing. My first suggestion is to stop reading the case histories and join some of the organizations out there that support AA and MDS patients. You will find there are a lot more success stories.