Congenital myasthenia syndrome with demyelinating sensorimotor neuropathy responsive to salbutamol monotherapy: a novel clinical phenotype of CHRNE mutation

Excerpt

Sir: Congenital myasthenic syndromes are a rare heterogeneous group of disorders affecting the neuromuscular junction, resulting from several genetic mutations [1]. These syndromes usually have an early onset (usually < 20 years), a positive family history, and usually never respond to immunomodulatory drugs, often not even to pyridostigmine [1, 2]. More than 30 pathogenic genes encoding for distinct proteins expressed at the neuromuscular junction have been identified [2]. The primary genes known to harbor pathogenic mutations that affect the acetylcholine receptor (AChR) subunits are CHRNE, CHRNA1, CHRNB1, and CHRND. Mutations in these genes are closely associated with AChR deficiency and the resultant kinetic dysfunction. Such genetic alterations lead to the impaired functioning of the AChR, a crucial component in neuromuscular transmission [1, 2]. Identifying the genetic basis of each congenital myasthenic syndrome is essential for genetic counseling, disease prevention, and therapy because therapeutic agents that benefit one type of congenital myasthenic syndrome can be ineffective/harmful in another [1, 2]. …