Objective: To explore the clinical features of a Chinese pedigree affected with skeletal muscle sodium channelopathies due to variation of SCN4A gene.
Methods: Potential variation of the 24 exons of the SCN4A gene was screened using PCR and Sanger sequencing.
Results: Four family members were affected with the disease in an autosomal dominant inheritance pattern. Three patients had normekalemic periodic paralysis, while 1 showed paramyotonia congenita. Genetic analysis detected a missense variation c.2078T>C (p.Ile693Thr) in exon 13 of the SCN4A gene in the proband and other 3 affected relatives.
Conclusion: Normokalemic periodic paralysis and paramyotonia congenita can occur in different family members with skeletal muscle sodium channelopathies due to c.2078T>C(p.Ile693Thr) variation of SCN4A gene.