🧠 Neurological Disorder

Congenital Myasthenic Syndrome

Also known as: CMS, Familial infantile myasthenia, Myasthenic syndrome, congenital

Congenital myasthenic syndromes (CMS) are a heterogeneous group of inherited disorders affecting neuromuscular transmission. They are characterized by muscle weakness and fatigability, typically presenting in infancy or early childhood, although later onset is possible. CMS arises from genetic defects affecting various components of the neuromuscular junction, leading to impaired signal transmission between nerve and muscle.

ICD-10: G70.2 Orphanet: 608 OMIM: 601462
👥 Estimated 1 in 500,000 Prevalence
🔬 15 Active Trials

Imagine your muscles need a message to move, like a text message. In CMS, the message doesn't get through properly, so your muscles get tired easily. It's like having a weak signal for your muscles.

Signs & Symptoms

  • Muscle weakness
  • Fatigability
  • Ptosis (drooping eyelids)
  • Diplopia (double vision)
  • Difficulty swallowing (dysphagia)
  • Feeding difficulties in infants
  • Respiratory insufficiency
  • Limb weakness
  • Hypotonia (decreased muscle tone) in infants
  • Delayed motor milestones

Treatment Options

MEDICATION FDA Approved

Cholinesterase inhibitors (e.g., pyridostigmine)

MODERATELY EFFECTIVE
MEDICATION

3,4-Diaminopyridine (3,4-DAP)

MODERATELY EFFECTIVE
MEDICATION FDA Approved

Albuterol

MODERATELY EFFECTIVE
MEDICATION FDA Approved

Ephedrine

MODERATELY EFFECTIVE
SUPPORTIVE

Supportive care (e.g., respiratory support, feeding assistance)

SUPPORTIVE
THERAPY

Physical therapy

SUPPORTIVE
THERAPY

Occupational therapy

SUPPORTIVE
GENE THERAPY

Gene therapy (experimental)

EXPERIMENTAL

Diagnosis

  • Clinical evaluation
  • Electrophysiological studies (repetitive nerve stimulation, single-fiber EMG)
  • Genetic testing (gene panel or exome sequencing)
  • Muscle biopsy (in some cases)
  • Pharmacological testing (response to cholinesterase inhibitors)

History

The first descriptions of congenital myasthenic syndromes date back to the early 20th century, but the genetic basis of these disorders has only been elucidated in recent decades. Advancements in molecular genetics have led to the identification of numerous genes associated with CMS, improving diagnostic accuracy and enabling more targeted therapeutic approaches.

Recent Breakthroughs

2022

Novel Gene Discoveries in Congenital Myasthenic Syndromes

Identification of new genes associated with CMS expands the genetic landscape and improves diagnostic capabilities.

2023

Advancements in Gene Therapy for CMS

Preclinical studies show promise for gene therapy approaches in specific forms of CMS, offering potential for disease modification.