Congenital myasthenic syndrome (RAPSN gene)

Congenital myasthenic congenital syndrome (CMS) is a group of rare inherited disorders that affect neuromuscular transmission and result in a condition of muscle weakness that is accentuated by exertion. In most cases CMS begins in early childhood, but it is possible for it to begin in adulthood. It may be inherited autosomal recessively or dominantly.

Up to 35 genes are involved in this group of disorders, which are classified into 14 groups according to pathomechanical characteristics.

The main symptoms of CMS include muscle fatigue, muscle weakness, muscle hypoplasia, and minor facial abnormalities such as low-set ears and high-arched palate in some patients.

As mentioned, there are 14 types of congenital myasthenic congenital syndrome, each with a variety of structural abnormalities in the neuromuscular junction. The pattern of inheritance, clinical symptoms, electrophysiology, and response to therapy vary depending on the type. Some of the subtypes that may be encountered include: “familial myasthenia infantile” and “congenital absence of acetylcholinesterase” which usually presents in childhood or adolescence with generalized weakness and decreased muscle tone.

Symptom management and drug treatment depends on the type of CMS. When the affected gene is RAPSN, drugs that can alleviate symptoms such as cholinesterase inhibitors are available.