A novel murine myotonia congenita without molecular defects in the ClC-1 and the SCN4A

The authors report a new murine model for myotonia congenita designated as B6MT. This line spontaneously arose from breeding of transgenic C57BL/6CrSlc mice, irrelevant of the transgene. The B6MT mouse showed moderate to severe action myotonia, and electromyography revealed myotonic discharge. The phenotype was transmitted with autosomal recessive inheritance. Molecular genetic study of the ClC-1 and the SCN4A genes revealed polymorphism with no functional consequences.