There are different types of policies and companies vary in their policies. Whole life, the type that builds a cash payout over time may be unavailable to you; but term life, which pays out a sum certain in the event that you die during the coverage period may be avaiable. Contact an Insurance broker.
It depends upon the condition; if it is certain to be fatal, it is unlikely that you can get insurance. For more minor conditions, however, if you fully disclose that you have the condition, you should be able to get life insurance. Your premiums will be higher, but the coverage is available.
Usually insurance companies would not cover pre-existing conditions because of high probablility that it will develop into an illness - it`s too risky for them.
It will be hard to find a insurance company that will cover pre-existing contidions. If you find one it will cost you plenty. You would be better off buying CD's or an IRA.