Neuronal ceroid lipofucinosis

Neuronal ceroid lipofucinosis is a group of related terminal genetic disorders where a group of fats and proteins accumulate around the body's neurons and in the organs. They first cause a loss of motor and physiological function and eventually lead to death. Even collectively, they are rare, occurring in about 1 in 10,000 people. The conditions all progress in the same manner, but differ in the onset age, speed of progression, initial symptoms and the organs affected. Vision loss and seizures are typically the first symptoms.
Although there are several experimental therapies including gene therapy and stem cell therapy, these can only slow the progress of the condition and cannot reverse existing damage. As such, treatment usually involves addressing symptoms and keeping the patient comfortable. 
Neuronal ceroid lipofucinosis at Wikipedia