CLCN1 and Myotonia: In contrast, a recessive myotonia mutation involves a missense mutation at the pore-lining M485 (M485V) that drastically changes the voltage-dependent gating and the single-channel conductance of homodimeric mutant CLC-1 channels; upon co-expression with the WT subunit, however, the M485V mutant fails to detectably affect the gating or conductance properties of heterodimeric ClC-1 channels (94).