(S (S (BASENP (NN MS)) (VP (VBZ is) (NP (NP (BASENP (DT an) (JJ autoimmune) (NN disease)) (PP (IN of) (BASENP (DT the) (ADJP (JJ central) (JJ nervous)) (NN system)))) (SBAR (WHADVP (WRB where)) (S (BASENP (DT the) (NN body)) (VP (VP (VBZ attacks) (NP (BASENP (DT the) (JJ fatty) (NN myelin)) (SBAR (WHNP (WDT which)) (S (VP (VBZ helps) (S (BASENP (NNS nerves)) (VP (VB carry) (BASENP (JJ electrical) (NNS signals))))))))) (COMMA ,) (S (VP (VBG causing) (NP (NP (BASENP (NN muscle) (NN weakness)) (CC and) (BASENP (NN spasming))) (SBAR (WHNP (WDT which)) (S (VP (MD may) (VP (VB lead) (PP (TO to) (BASENP (NN disability)))))))))))))))) (PERIOD .))