Rare Endocrinology News
Disease Profile
Congenital myasthenic syndromes
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
1-9 / 1 000 000
Age of onset
Infancy
ICD-10
G70.2
Inheritance
Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.
Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.
X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.
X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.
Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.
Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.
Not applicable
Other names (AKA)
CMS; Congenital Myasthenia; Congenital myasthenic syndrome
Summary
Symptoms
- Muscle weakness that is brought on by activity or exercise
- Eyelid drooping which can come and go
- Facial and throat muscle weakness
- Delay of motor development
Many subtypes of CMS have specific symptoms that help identify them. For example, muscle weakness in the limbs and torso is most often seen in the COLQ, DOK7, and GFPT1 subtypes, and difficulty breathing is seen most often in the CHRNE and CHAT subtypes.[3][4]
This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.
Medical Terms | Other Names |
Learn More:
HPO ID
|
---|---|---|
80%-99% of people have these symptoms | ||
Poor swallowing
Swallowing difficulties
Swallowing difficulty
[ more ] |
0002015 | |
Fatigable weakness | 0003473 | |
Frontalis muscle weakness |
Weakness of forehead muscle
|
0004661 |
Intermittent episodes of respiratory insufficiency due to muscle weakness | 0004889 | |
Neck muscle weakness |
Floppy neck
|
0000467 |
Poor suck |
Poor sucking
|
0002033 |
Proximal muscle weakness |
Weakness in muscles of upper arms and upper legs
|
0003701 |
Drooping upper eyelid
|
0000508 | |
Sudden episodic apnea | 0002882 | |
30%-79% of people have these symptoms | ||
Apneic episodes precipitated by illness, fatigue, stress | 0002872 | |
Arthrogryposis multiplex congenita | 0002804 | |
0001251 | ||
Bulbar palsy | 0001283 | |
Central sleep apnea | 0010536 | |
Choking episodes | 0030842 | |
Cyanosis |
Blue discoloration of the skin
|
0000961 |
Decreased fetal movement |
Less than 10 fetal movements in 12 hours
|
0001558 |
Difficulty walking |
Difficulty in walking
|
0002355 |
Easy fatigability | 0003388 | |
EMG: impaired neuromuscular transmission | 0100285 | |
Episodic respiratory distress |
Episodic difficulty breathing
|
0004885 |
Generalized muscle weakness | 0003324 | |
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] |
0001249 | |
Muscle fiber atrophy |
Muscle fiber degeneration
|
0100295 |
Nasal regurgitation | 0011469 | |
Nasal speech |
Nasal voice
|
0001611 |
Ophthalmoplegia |
Eye muscle paralysis
|
0000602 |
Recurrent respiratory infections |
Frequent respiratory infections
Multiple respiratory infections
respiratory infections, recurrent
Susceptibility to respiratory infections
[ more ] |
0002205 |
Spinal deformities | 0008443 | |
5%-29% of people have these symptoms | ||
Areflexia |
Absent tendon reflexes
|
0001284 |
Central |
0011398 | |
Distal amyotrophy |
Distal muscle wasting
|
0003693 |
Distal lower limb muscle weakness | 0009053 | |
Dysphonia |
Inability to produce voice sounds
|
0001618 |
EMG: myopathic abnormalities | 0003458 | |
High palate |
Elevated palate
Increased palatal height
[ more ] |
0000218 |
Kyphoscoliosis | 0002751 | |
Limb-girdle muscle weakness | 0003325 | |
Long face |
Elongation of face
Increased height of face
Increased length of face
Vertical elongation of face
Vertical enlargement of face
Vertical overgrowth of face
[ more ] |
0000276 |
Motor delay | 0001270 | |
Narrow jaw |
Narrow lower face
Narrow lower jaw
[ more ] |
0012801 |
Pes cavus |
High-arched foot
|
0001761 |
Poor head control | 0002421 | |
0001250 | ||
Spinal rigidity |
Reduced spine movement
|
0003306 |
Stridor | 0010307 | |
Toe walking |
Toe-walking
|
0040083 |
Waddling gait |
'Waddling' gait
Waddling walk
[ more ] |
0002515 |
Weak cry | 0001612 | |
1%-4% of people have these symptoms | ||
Congenital hip dislocation |
Dislocated hip since birth
|
0001374 |
Diplopia |
Double vision
|
0000651 |
0002392 | ||
Esotropia |
Inward turning cross eyed
|
0000565 |
Gastroesophageal reflux |
Acid reflux
Acid reflux disease
Heartburn
[ more ] |
0002020 |
Hyporeflexia |
Decreased reflex response
Decreased reflexes
[ more ] |
0001265 |
Joint laxity |
Joint instability
Lax joints
Loose-jointedness
Loosejointedness
[ more ] |
0001388 |
Low-set ears |
Low set ears
Lowset ears
[ more ] |
0000369 |
Microretrognathia |
Small retruded chin
|
0000308 |
Motor polyneuropathy | 0007178 | |
Involuntary, rapid, rhythmic eye movements
|
0000639 | |
Obstructive sleep apnea |
CauseDiagnosis
Other testing might include [3]: Treatment There is no single treatment for
The response to medication is different from person to person. Genetic diagnosis of the specific sub-type of CMS is important because a medication that benefits one type of CMS can make another type worse.[3] Specialists that may be involved in the care of people with CMS include:[1][3]
OrganizationsSupport and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD. Organizations Supporting this Disease
Organizations Providing General Support
Learn moreThese resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional. Where to Start
In-Depth Information
References
Rare Endocrinology News |