Is there really a werewolf syndrome?

Yes: Acute intermittent porphyria used to be called the werewolf syndrome. It does not mean that these patients are werewolves. Many have some symptoms, such as excessive hair growth and red urine, that reminded people of werewolves.

Not Specifically: There is a disease called hypertrichosis, or ambras syndrome, where people develop excessive body hair. It's a genetic syndrome that can be present at birth or develop later in life as a result of things like cancer or certain hormonal imbalances.