Complex sentence: Studies propose that his illness was a syndrome known as Vogt-Koyanagi-Harada, or uveomeningoencephalytic syndrome--an autoimmune disorder which involves the visual and cochlear pigment derived from the neural crest.
Split into simpler sentences: Studies propose that his illness was a syndrome known as Vogt-Koyanagi-Harada, or uveomeningoencephalytic syndrome. This is an autoimmune disorder which involves the visual and cochlear pigment derived from the neural crest.