Huntington’s disease suffer Jack, has discovered a power in which can prevent the death of his closest friend Gracie, he must defeat the odds and find a way to communicate or have to witness her deteriorate in front of him.

This seems an intriguing plot, very high stakes, and a very strong ticking clock. But it seems a little unclearly presented. From what I understand Huntington's affects movement. ...... What about something along the lines of ... When a Huntington's disease sufferer stumbles on a cure for his dying friend, he must find a way to regulate his movements to communicate it to her .....

I feel perhaps it is a little bit too long. remember strong loglines often start with when, after, as. Also alot of people will not know what Huntington's disease is and therefore will not be able to understand why jack is unable to communicate with gracie.

perhaps something like this?
"After jack discovers a power which will prevent the death of his closest friend, but first he must overcome his own illness in order to save her."

good luck