demyelinating disease       
noun [ U ]  medical specialized uk/diːˈmaɪ.ə.lɪ.neɪt.ɪŋ dɪˌziːz/ us/diːˈmaɪ.ə.lɪˌneɪ.t̬ɪŋ dɪˌziːz/
 脱髓鞘病,髓鞘脱失病
a disease that damages myelin (= a white fatty substance that covers some nerves)
  Multiple sclerosis is the most common demyelinating disease. 多发性硬化症是最常见的髓鞘脱失病。