I just wanted to add one thing, which is, if you have insurance, most insurors will want the DNA testing ordered by a neurologist, and won't honor an order by a primary care physician. They want the neurologist to evaluate and ascertain that the test is warranted.
I had mine done through Athena, but had to specifically petition for it, because my insurance company didn't realize how specialized the test was, and wanted their contracted lab to do it - so that lab had to verify that they don't/can't do that test, and then Athena sent an RN to my home, specifically to draw the blood and send it to Athena.
My insurance had pre-approved the whole process, including a broader spectrum of testing - but when they realized how costly it was, they reneged on their approval, and re-issued an authorization for the CLCN1 test (I think that's what it's called - my mind is presently distracted by Doberman Pinschers!) only.
Getting the results took a few months. Lois
Type of Myotonia: Myotonia Congenita, Becker's type