Rinsho Shinkeigaku (Clinical Neurology)

Case Report

Beneficial effects of 3,4-diaminopyridine in a 26-year-old woman with DOK7 congenital myasthenic syndrome who was originally diagnosed with facioscapulohumeral dystrophy

Atsuko Nishikawa, M.D.1), Madoka Mori-Yoshimura, M.D., Ph.D.1), Tomoko Okamoto, M.D., Ph.D.1), Yasushi Oya, M.D., Ph.D.1), Tomohiko Nakata, M.D., Ph.D.2), Kinji Ohno, M.D., Ph.D.2) and Miho Murata, M.D., Ph.D.1)

1)Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry
2)Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine

We report a 26-year-old woman who had respiratory dysfunction and muscle weakness at birth and was diagnosed with facioscapulohumeral dystrophy at the age of 5. The extent of muscle weakness fluctuated daily or weekly and deteriorated in menstrual periods. At the age of 12, she noted improvements in symptoms when taking procaterol hydrochloride and began to take it regularly. After that, her condition stabilized. At the age of 26, she visited our hospital presenting with ptosis, muscle weakness in the face, trunk, and proximal limbs, and easy fatigability. Serum CK was normal; anti-acetylcholine receptor and anti-muscle specific tyrosine kinase antibodies were negative. A repetitive stimulation test in the trapezius muscle showed a waning phenomenon. Gene analysis for congenital myasthenic syndrome (CMS) revealed a new mutation in the DOK7 gene; the diagnosis of CMS was confirmed. Her symptoms worsened with ambenonium chloride but improved with 3,4-diaminopyridine. Our findings suggest that daily or weekly fluctuation and worsening with a menses in muscle weakness is an important diagnostic feature of CMS.
Full Text of this Article in Japanese PDF (1582K)

(CLINICA NEUROL, 54: 561|564, 2014)
key words: congenital myasthenic syndrome, 3,4-diaminopyridine, endplate AchR deficiency, DOK7, ptosis

(Received: 19-Aug-13)