Allan Herndon Dudley Syndrome

Allan-Herndon-Dudley Syndrome is an extremely rare condition that is only known to affect approximately 25 people in the entire world.

Researchers believe that a X-linked trait is the cause and therefore, only males experience the disorder. People that suffer from this disorder are severely mentally retarded and have a hard time speaking clearly and putting words together.

The disorder is also characterized by decreased muscle tone. Generally, infants will appear normal until approximately six months old. It is at this time that parents and caregivers notice physical developmental delays.