A 17 years old girl with neuroregression that started at 4 years of age. She had been developmentally normal until the age of 4 years when she started to gradually lose her ability to walk and talk, and she is currently wheelchair-bound. She communicates through nodding her head. She also has developed seizures, but they have been under control. The parents are first-degree cousins, and they have three other affected children and three deceased children who died for an unknown reason. On examination, her growth parameters were weight 32 kg (<3rd percentile) and head circumference 49 cm(<3rd percentile). She has an ulnar deviation of the hands. She also has hyperreflexia of the extremities and strabismus. MRI showed mild leukodystrophy. Skin biopsy showed inclusion bodies. 