Kennedy's condition is called spasmodic dysphonia, which is a neurologic disorder that can affect the voice and speech by causing the muscles that generate a person’s voice to go into periods of spasm, according to Penn Medicine. It is a lifelong condition, but can be improved with treatment in some cases, according to Penn Medicine.

Robert F. Kennedy Jr. has spasmodic dysphonia, a voice disorder caused by a malfunction in the brain. Here’s what to know.

The health committee chairman, Sen. Bill Cassidy, R-La., also has expressed concerns about Kennedy's anti-vaccine work. A physician, Cassidy said earlier this month he “had a frank conversation” and “spoke about vaccines at length” with Kennedy. On Tuesday, Cassidy told reporters that he is still unsure if he is backing Trump’s nominee.

Kathleen "Kick" Kennedy is the eldest daughter of Robert F. Kennedy Jr., who could be confirmed as health secretary in Trump's administration.

One of the hottest topics in the coverage of his confirmation hearing was RFK Jr.'s unusually gruff speaking voice. But the raspy sound to his voice is not the result of an infection or respiratory condition;