Targeted pharmacotherapy for trafficking defective ClC-1 mutations in myotonia congenita

A delayed muscle relaxation after a voluntary contraction is the main clinical feature of myotonia congenita (MC). MC is a skeletal muscle channelopathy caused by loss-of-function mutations in the ClC-1 chloride channel, which impair channel function or plasma membrane expression. To date, no direct activator of ClC-1 channel is known. A potential strategy may be to restore surface expression of trafficking-defective ClC-1 mutants by using pharmacological chaperones. Thus, we tested the ability of niflumic acid (NFA), a reversible inhibitor of ClC-1, to restore membrane expression of MC ClC-1 mutants (A531V, V947E, G411C).