OBJECTIVES To characterise the clinical and electrophysiological features and to determine the molecular genetic basis of pure paramyotonia congenita in a previously unreported large Irish kindred. METHODS Clinical and neurophysiological examination was performed on three of the five affected family members. Five unaffected and three affected members of the family were available for genetic t...

Ion channel disorders are rare inherited diseases providing interesting models to study dysfunction of excitability in vivo and in vitro. The first socalled ‘channelopathies’ identified were skeletal muscle diseases, the myotonias and hyperkalemic periodic paralysis (HyperPP), which are sodium or chloride channel disorders. Within the last 5–10 years, complementary genetic and electrophysiologi...

The inherited diseases hyperkalemic periodic paralysis and paramyotonia congenita are caused by mutations in the adult skeletal muscle sodium channel gene. To determine if differences in the expression patterns of the adult and cardiac/fetal sodium channel genes could explain some clinical features of these disorders, we developed a novel mRNA quantitation strategy called quantitative multiplex...

Missense mutations of the human skeletal muscle voltage-gated Na channel (hSkM1) underlie a variety of diseases, including hyperkalemic periodic paralysis (HyperPP), paramyotonia congenita, and potassium-aggravated myotonia. Another disorder of sarcolemmal excitability, hypokalemic periodic paralysis (HypoPP), which is usually caused by missense mutations of the S4 voltage sensors of the L-type...

BACKGROUND Paramyotonia congenita (PMC) of von Eulenburg is an autosomal dominant muscular disease characterized by exercise- and cold-induced myotonia and weakness. To date, 18 missense mutations in the adult skeletal muscle sodium channel alpha-subunit (SCN4A) gene have been identified to cause a spectrum of muscular diseases, including PMC of von Eulenburg, PMC without cold paralysis, potass...