SCN4A and periodic paralysis: He also carried a c.2717G > C base exchange in SCN4A gene, predicting an S906T substitution considered a benign polymorphism with a frequency of about 1.5% in the European population according to the Genome Aggregation Database (gnomAD) and described in patients with neurological diseases not related to channelopathies or with either hypo- or hyperkalemic periodic paralysis with a frequency of about 5%6.