According to ABC News, Robert F. Kennedy Jr. suffers from “spasmodic dysphonia, a specific form of an involuntary movement disorder called dystonia that affects only the voice box.” This is not a life-threatening illness but it can certainly affect one’s quality of life.
Having endured dysphonia for some ten years now (there is no known cause), I must say I admire him to plow ahead with his handicap. Speaking with dysphonia is like driving a car with the parking brake on.