De novo variant in SCN4A causes neonatal sodium channel myotonia with general muscle stiffness and...

De novo variant in SCN4A causes neonatal sodium channel myotonia with general muscle stiffness and..., Non-dystrophic myotonias are a rare group of neuromuscular disorders caused by variants in skeletal muscle sodium (SCN4A) or chloride (CLCN1) channels genes. Variants in SCN4A are associated with different phenotypes such as paramyotonia congenita, hyper- or hypokalemic periodic paralysis, sodium channel myotonia but also with congenital myasthenic syndromes and congenital myopathies [1, 2]., Non-dystrophic myotonias are a rare group of neuromuscular disorders caused by variants in skeletal muscle sodium (SCN4A) or chloride (CLCN1) channels genes. Variants in SCN4A are associated with different phenotypes such as paramyotonia congenita, hyper- or hypokalemic periodic paralysis, sodium channel myotonia but also with congenital myasthenic syndromes and congenital myopathies [1, 2]. Clinical symptoms are mainly characterized by episodes with muscle stiffness or paralysis triggered by exercise, cold, infections or fasting [2, 3]., admin,