Ephedrine therapy in eight patients with congenital myasthenic syndrome due to DOK7 mutations

Received 25 August 2009; accepted 21 September 2009.

Abstract

In congenital myasthenic syndrome with DOK7 mutations ephedrine was reported to be beneficial in single patients. We carried out a small, open and prospective cohort study in eight European patients manifesting from birth to 12years. Five patients showed limb-girdle and facial weakness, three a floppy infant syndrome with bulbar symptoms and/or respiratory distress. Ephedrine was started with 25mg/day and slowly increased to 75–100mg/day. Within weeks after starting therapy an improvement was observed in all patients and clinical follow-up disclosed positive effects more pronounced on proximal muscle weakness and strength using MRC scale. Effects on facial weakness were less pronounced. Vital capacity measurements and repetitive stimulation tests did not improve in the same way as clinical symptoms did. These investigations are appropriate to confirm the diagnosis in case of pathological results, but they might not be appropriate means to monitor patients under ephedrine therapy.

Keywords: Congenital myasthenic syndrome, Synaptopathy, Downstream-of-kinase-7, DOK7, Ephedrine therapy

a Dept. of Pediatric Neurology, University of Essen, Germany

b Dept. of Pediatrics, Clinical Medical Center, University of Zagreb, Croatia

c Dept. of Neurology, Martin-Luther-University, Halle-Wittenberg, Germany

d Neuromuscular Centre, Sahlgrenska University Hospital, Gothenburg, Sweden

e Institute of Human Genetics, University of Newcastle upon Tyne, Newcastle upon Tyne, UK

f Friedrich-Baur-Institute, Dept. of Neurology, Ludwig-Maximilians-University, Munich, Germany

Corresponding author. Address: Dept. of Pediatric Neurology, University of Essen, Hufelandstr. 55, D-45122 Essen, Germany. Tel.: +49 201 723 2356; fax: +49 201 723 5389.

PII: S0960-8966(09)00622-1

doi:10.1016/j.nmd.2009.09.008

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