Screening SCN4A gene for mutations with denaturing high performance liquid chromatography technology in a Chinese family with normokalemic periodic paralysis

Abstract

To study the clinical features of normokalemic periodic paralysis (normoKPP) and to confirm the relation between Met1592Val mutation and normoKPP and clarify its clinical features. The clinical features of 14 patients in a Chinese family of normoKPP were summarized. All 24 exons of SCN4A gene were screened with denaturing high performance liquid chromatography (DHPLC) technology, and then sequence analysis was performed on those with abnormal elution peak. This family showed typical clinical features of normoKPP without myotonia. The progress of most patients was benign. Two missence mutations were found in exon 1 and exon 24 respectively. Linkage analysis and direct sequencing showed the mutation in exon 1 was g189a, a benign polymorphism, and the mutation Met1592Val in exon 24 was responsible for this disease. The mutation Met1592Val does exist in Chinese patients, and lead to normoKPP. NormoKPP is similar to hyperKPP not only in clinical futures but also in genetic level.