These days, popular media has made polydactylism a well-known genetic anomaly. From Gravity Falls to The Princess Bride, tons of fictional characters have more than five digits on their hands or feet. However, not everyone knows what Ulnar Dimelia is, in part because less than 100 cases have ever been diagnosed. People affected by Ulnar Dimelia can have a second hand attached to their wrist that mirrors the movements of the first. For this reason, Ulnar Dimelia is colloquially known as mirror hand syndrome.
As of 2018, researchers are still discovering new mirror hand syndrome facts on a regular basis. The disease doesn't seem to be hereditary, and it may be caused by a genetic mutation. Unfortunately, this is just a hypothesis, as no one knows exactly what causes the rare hand condition.
Less Than 100 Cases Of Mirror Hand Syndrome Have Been Recorded
The Syndrome Can Duplicate Fingers, Or A Whole Hand
Hands Affected By Ulnar Dimelia Usually Don't Have Thumbs
The Connected Hands Move In Unison
The Syndrome Can Be Classified Into Five Different Types
Ulnar Dimelia Can Impede The Entire Arm's Range Of Motion