KLHL40-related nemaline myopathy with a sustained, positive response to treatment with acetylcholinesterase inhibitors

J Neurol. 2016 Mar;263(3):517-23. doi: 10.1007/s00415-015-8015-x. Epub 2016 Jan 11.


Congenital myopathies are a group of inherited muscle disorders characterized by hypotonia, weakness and a non-dystrophic muscle biopsy with the presence of one or more characteristic histological features. Neuromuscular transmission defects have recently been reported in several patients with congenital myopathies (CM). Mutations in KLHL40 are among the most common causes of severe forms of nemaline myopathy. Clinical features of affected individuals include fetal akinesia or hypokinesia, respiratory failure, and swallowing difficulties at birth. Muscle weakness is usually severe and nearly half of the individuals have no spontaneous antigravity movement. The average age of death has been reported to be 5 months in a recent case series. Herein we present a case of a patient with a nemaline myopathy due to KLHL40 mutations (c.604delG, p.Ala202Argfs*56 and c.1513G>C, p.Ala505Pro) with an impressive and prolonged beneficial response to treatment with high-dose pyridostigmine. Myasthenic features or response to ACEI have not previously been reported as a characteristic of nemaline myopathy or KLHL40-related myopathy.

Keywords: Acetylcholinesterase inhibitors; Congenital myasthenic syndromes; Congenital myopathies; KLHL40; Nemaline myopathies; Neuromuscular junction.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cholinesterase Inhibitors / therapeutic use*
  • Female
  • Humans
  • Infant
  • Longitudinal Studies
  • Muscle Proteins / genetics*
  • Muscle Proteins / metabolism
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / pathology
  • Myopathies, Nemaline / drug therapy*
  • Myopathies, Nemaline / genetics*
  • Myopathies, Nemaline / pathology
  • Neurologic Examination


  • Cholinesterase Inhibitors
  • KLHL40 protein, human
  • Muscle Proteins