Stiffness as a presenting symptom of an odd clinical condition caused by multiple sclerosis and myotonia congenita. Portaro S, Musumeci O, Rizzo V, Rodolico C, Sweeney MG, Buccafusca M, Hanna MG, Toscano A Neuromuscul Disord. 2012 Aug 23. PMID: 22921319. Abstract CommentRecommendBookmarkWatch