Treatment of Becker myotonia congenita with lamotrigine: one case report and review of literatures

Abstract

Objective To report the efficacy and safety of lamotrigine in the treatment of one case of Becker myotonia congenita. Methods and Results A 17-year-old male had muscle stiffness in the limbs as the first symptom, which could be alleviated after repeated exercise. The creatine kinase (CK) level was normal. Genetic testing showed there were two missense mutations c.1205C > T (p.Ala402Val) and c.896T > C (p.Val299Ala) located in exon 11 and 8 of CLCN1 gene respectively in the proband. The missense mutation c.1205C > T (p.Ala402Val) in exon 11 was found out in his mother and c.896T > C (p.Val299Ala) located in exon 8 was found out in his father. The latter, exon 8 c.896T > C of CLCN1 gene has not been reported. The proband was clearly diagnosed as Becker myotonia congenita, and his family was diagnosed as Becker myotonia congenita pedigree. After 5 years' treatment with lamotrigine, the symptom of myotonia was significantly improved and no adverse reactions was observed. Conclusions The missense mutation in exon 8 c.896T > C in this patient further expanded the CLCN1 gene mutation spectrum. Lamotrigine is effective in treating Becker myotonia congenita, providing a new idea for the treatment of myotonia congenita.

DOI: 10.3969/j.issn.1672-6731.2019.05.009