Background:CLCN1-related myotonia congenita (MC) is one of the most common forms of non-dystrophic myotonia. in which muscle relaxation is delayed after voluntary or evoked contraction. However. there is limited data of clinical and molecular spectrum of MC patients in China. https://www.bekindtopets.com/hot-find-Synovex-One-Grass-Extended-Release-Implant-10-Dose-special-find/