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A Spotlight on Allan-Herndon-Dudley

Feb 26, 2020 | Article

In advance and support of Rare Disease Day taking place this Saturday, February 29, we will continue featuring rare diseases throughout the week to bring awareness to these uncommon, yet impactful illnesses. 

Those living with rare diseases often experience significant delays in diagnosis and access to treatment options. The Orphan Drug Act of 1983 created financial incentives to develop new drugs for rare diseases and, as a result, research has increased. However, there are still more than 7,000 different rare diseases that exist today, of which only 5% have treatments. Mitchell Herndon had a disease so rare that there was no name for it. As one of only two known patients in the world, he grappled with a reality that saw him as a case study for doctors who are only beginning to learn about his condition. In October of 2019, Mitchell passed away after doctors discovered the disease had infiltrated his brain.

ALLAN-HERNDON-DUDLEY SYNDROME is a rare disorder of brain development that causes moderate to severe intellectual disability and problems with movement. This condition, which occurs exclusively in males, disrupts development from before birth. Most children with Allan-Herndon-Dudley syndrome have weak muscle tone (hypotonia) and underdevelopment of many muscles (muscle hypoplasia). As they get older, they usually develop joint deformities called contractures, which restrict the movement of certain joints. Abnormal muscle stiffness (spasticity), muscle weakness, and involuntary movements of the arms and legs also limit mobility. As a result, many people with Allan-Herndon-Dudley syndrome are unable to walk independently and become wheelchair-bound by adulthood.  It is approximated that there are currently a reported 25 families with individuals affected by this condition worldwide. See what it’s like to live with the rarest of rare.