I've been diagnosed with Cramp Fasciculation Syndrome. I always assumed I had Isaac's Syndrome because of the severity of my symptoms, but nothing has turned up in blood tests. EMGs see lots of fasciculations, but no doublets or triplets which denote Isaac's. The Mayo clinic was able to induce cramping during their EMG test, hence the CFS diagnosis.
I definitely cramp,

Also loads of:
Stiffness
Muscle jerks and general shakiness
Lots of pain. Burning nerve pain but also super deep aches.
Delayed muscle relaxation
Hyperhydrosis (excessive sweating, hot flashes, night sweats, etc)
Sleep walking/night terror type stuff
Loss of cooridnation
I used to get 50+ cramps per day but my Doc put me on Mexiletine which has taken 95% of the cramping away.
I've had it for around 20 years. It started as very light twitching and cramping in the calves when I was 13 and has steadily progressed to where it is now.