(S (S (S (BASENP (DT The) (NN breakthrough)) (VP (VBZ involves) (NP (BASENP (DT a) (NN gene)) (VP (VBN known) (PP (IN as) (NP (BASENP (NNP TRESK)) (COMMA ,) (VP (VBN thought) (S (VP (TO to) (VP (VB control) (NP (NP (BASENP (DT the) (NN brain) (POS 's)) (NN reaction)) (PP (TO to) (BASENP (NN pain)))))))))))))) (COLON :) (S (SBAR (IN if) (S (BASENP (PRP it)) (VP (VBZ is) (ADJP (JJ defective))))) (COMMA ,) (S (ADVP (RB then)) (S (NP (JJ many) (BASENP (JJ normal) (NNS activities) (CC and) (NNS actions))) (VP (MD will) (VP (VB be) (ADJP (JJ painful)))))))) (PERIOD .))