Hillenburg gave a statement about his diagnosis:
"I wanted people to hear directly from me that I have been diagnosed with ALS. Anyone who knows me knows that I will continue to work on 'SpongeBob SquarePants' and my other passions for as long as I am able. My family and I are grateful for the outpouring of love and support. We ask that our sincere request for privacy be honored during this time."
source: information & quote from NBC News