To get tested or not to get tested

My cousin has a rare disease called Huntington's Disease.
Huntington's disease - Wikipedia, the free encyclopedia
It's a genetic disease that basically destroys your nervous system. It usually doesn't affect you until your late 40's.
They can test your genes for it at any age. But if you are diagnosed with it, you will never be able to get health insurance for the rest of your life.

So here's the question;
Would you want to;
Know if you are going to develop it later, pretty much guaranteeing you won't live through your 50s and never be able to have health insurance? But make sure and do all the things you've wanted to do, knowing you won't be able to do them when you're older. Plus there's the chance you might test negative.
or
Take your chances and say whatever will be, will be.