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Novel ϵ subunit mutation of the muscle acetylcholine receptor causing a slow-channel congenital myasthenic syndrome
  1. O Outteryck1,
  2. P Richard2,3,
  3. A Lacour1,
  4. E Fournier4,5,
  5. H Zéphir1,
  6. K Gaudon2,
  7. B Eymard3,4,
  8. D Hantaï3,4,
  9. P Vermersch1,
  10. T Stojkovic1,4
  1. 1
    Department of Neurology, University Hospital of Lille, Lille, France
  2. 2
    AP-HP, Functional Unit of Cardiogenetics and Myogenetics, Pitié-Salpêtrière Hospital, Paris, France
  3. 3
    INSERM U582, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France
  4. 4
    AP-HP, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France
  5. 5
    AP-HP, Federation of Clinical Neurophysiology, Pitié-Salpêtrière Hospital, Paris, France
  1. Dr O Outteryck, Department of Neurology, University Hospital of Lille, 59037 Lille, France; o-outteryck{at}chru-lille.fr

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The slow-channel congenital myasthenic syndrome is a frequent kinetic anomaly of the acetylcholine receptor (AChR). We report a family with a slow-channel congenital myasthenic syndrome that carries a novel mutation in the ϵ subunit of the AChR (p.Val259Leu). The family presents the classical clinical phenotype of slow-channel syndrome with phenotypic variability among the different members of the family.

Case reports

The propositus (patient II2, fig 1) is a 27-year-old woman. Myasthenic symptoms began at the age of 17 years just after her first delivery. She complained of distal and proximal weakness of the upper limbs and diplopia in lateral gaze. Clinical examination revealed ophthalmoparesis, bilateral ptosis a proximal weakness of the upper limbs involving predominantly the right shoulder and a weakness of the finger and wrist extensors. At each delivery, she presented a transient worsening of her myasthenic symptoms. Patient I1, the 53-year-old father of the propositus, was suspected of having cervical torticollis at the age of 5 years and underwent surgery, which proved ineffective. Bilateral ptosis, ophthalmoplegia and weakness of the finger and wrist extensors and cervical muscles have been present since childhood.

Figure 1

Pedigree of the family showing a presumably dominant inheritance. The arrow indicates the propositus (II2). The pathogenic role of the mutation was confirmed by the cosegregation, the conservation of residue and the absence of the mutation in …

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