Diseases of the neuromuscular junction
Congenital Myasthenic Syndromes (CMS)
Rare Disease Classifications:
IMPORTANT INFORMATION
The information on the Rare Awareness Rare Education (RARE) Portal is intended for educational purposes only and does not replace professional advice.
Rare diseases typically display a high level of symptom complexity and variability. Individuals diagnosed with the same rare disease may be impacted differently and each person’s experience is unique. Please seek support from qualified healthcare professionals to learn more about the most suitable care and support options for you.
If you are aware of any additional information that may benefit stakeholders with an interest in this page, or if you notice any broken links or inaccurate information, please let us know via the Contribute page.
Contributors
This page has been co-developed with RVA Partner, Myasthenia Alliance Australia, which represents Myasthenia Gravis Association of Queensland Inc. and The Australian Myasthenic Association in NSW.
Quick Page Search:
Emergency Management | Clinical Care Guidelines | Synonyms | Summary | Personal Stories | Symptoms | Cause/Inheritance | Diagnosis | Treatment | Clinical Care | Research and Data | Rare Disease Organisation(s) | Support Services/Resources | Mental Health | Other | References
Emergency Management
There may be special considerations for the emergency management of individuals living with congenital myasthenic syndromes (CMS) presenting to emergency departments.
It should be noted that treatment of an individual’s CMS symptoms may depend on the type of CMS and may differ from the treatment used for myasthenia gravis (MG). It has been recommended that a neurologist be consulted prior to administering medication.
Individuals with MG may carry a medical alert card that explains their specific condition and causal gene, as well as a list of general drugs that can exacerbate symptoms, which may provide useful information for emergency care.
Clinical Care Guidelines
We are not aware of any current clinical care guidelines for congenital myasthenic syndromes (CMS) in Australia. If you know of any relevant care guidelines, please let us know via the Contribute page.
GeneReviews®:Congenital Myasthenic Syndromes (Management) contains recommendations for evaluations following initial diagnosis, medical management in general and when possible, based on the genetic cause, as well as recommended surveillance for individuals with CMS.
Synonyms
Congenital Myasthenia; Congenital Myasthenic Syndrome
Summary
Congenital Myasthenic Syndromes (CMS) are a group of genetic neuromuscular conditions that affect the communication between nerve and muscle cells (neuromuscular transmission). CMS are characterised by muscle weakness which worsens with physical activity and mostly affects the muscles of the face, neck, throat, eyes and limbs.1,2 There are various subtypes of CMS3 which differ in symptoms, severity, and treatments.1 Approximately 30 genes have been associated with CMS so far, with genetic testing necessary to differentiate between the subtypes.1
CMS typically presents at birth or in early childhood, usually within the first decade of life.3 Symptoms range from mild to severe muscle weakness and may worsen over time or only occur periodically.1 CMS are sometimes misdiagnosed as other myasthenic conditions, such as Myasthenia Gravis and Lambert Eaton Myasthenic Syndrome which are autoimmune conditions and are not genetic.
Personal Stories
Congenital myasthenic syndromes (CMS) varies between individuals, and each person’s experience is unique.
If you would like to share your personal story with Rare Voices Australia and have it included on the RARE Portal, please visit Rare Voices Australia: Share Your Story.
Symptoms
Congenital myasthenic syndromes (CMS) are characterised by fatiguable weakness (weakness that worsens with physical activity and may improve temporarily with rest), mainly in the skeletal muscles such as muscles of the face, neck, throat, eyes and limbs, at birth or in early childhood.1-3
Other symptoms may present at birth, including feeding and respiratory difficulties, poor suck and cry, choking spells, noisy breathing (stridor) and drooping eyelid (ptosis).3 Some babies may have joint stiffness (contractures or arthrogryposis multiplex congenita) due to lack of movement in utero. There may also be delayed development of motor skills during childhood.3
Degeneration of muscle tissue (atrophy) is usually not observed with CMS, except for a specific CMS that is caused by defects in the GMPPB gene (GMPPB-related CMS).3
Please speak to your medical team to learn more about the symptoms and complications of a specific type of CMS.
Cause/Inheritance
Congenital myasthenic syndromes (CMS) are caused by genetic changes in specific genes that affect communication between nerve and muscle cells. More than 30 genes have been identified to cause CMS.3 Please visit GeneReviews®: Congenital Myasthenic Syndromes (Subtypes and Genetic Causes) for more information about the different types of CMS and the associated genes.
Most CMS are inherited in an autosomal recessive manner, however some mutations have been associated with an autosomal dominant effect.3 The following factsheets may be useful for understanding the inheritance pattern of a particular type of CMS:
- Autosomal recessive inheritance (NSW Government’s Health Centre for Genetics Education)
- Autosomal dominant inheritance (NSW Government’s Health Centre for Genetics Education)
If you would like to learn more about the inheritance and impact of this specific type of CMS, please ask your doctor for a referral to a genetic counsellor. Genetic counsellors are qualified allied health professionals who can provide information and support regarding genetic conditions and testing. More information on genetic counselling can be found on the National Services page and specific State and Territory Services pages on the RARE Portal.
Diagnosis
Diagnosis of congenital myasthenic syndromes (CMS) may involve a combination of medical and family history, physical examination, electromyography (EMG) testing to determine a defect in neuromuscular transmission as well as molecular genetic testing to identify the causal gene.3
Differential diagnosis information can be found at GeneReviews®: Congenital Myasthenic Syndromes (Differential Diagnosis of Congenital Myasthenic Syndromes).
Treatment
It is best to speak with your medical team to learn more about possible treatments for a specific type of congenital myasthenic syndromes (CMS) and its associated symptoms. Treatment will depend on the type of CMS as well as an individual’s specific symptoms and complications; each individual may respond to a particular treatment differently.
Clinical Care
Healthcare professionals involved in the treatment of congenital myasthenic syndromes (CMS) may include general practitioners (GP), genetic counsellors or clinical geneticists, neurologists, ophthalmologists, occupational therapists, speech pathologists, physiotherapists, and exercise physiologists.1 The need for different healthcare professionals may change over a person’s lifetime and extend beyond those listed here.
Clinics
Speciality Clinic for Myasthenia Gravis and Myasthenic Syndromes (NSW)
Department of Neurology
Concord Repatriation and General Hospital, Sydney
Ph: 02 9767 6416 / 02 9767 5623
Website: https://www.slhd.nsw.gov.au/concord/department-neurosciences-services.html
Neuroimmunology clinic provides services for patients with Neurological disorders with an immunologic basis including myasthenia gravis and multiple sclerosis and includes clinical research and access to clinical trials.
Neurology Service, Princess Alexandra Hospital (QLD)
Level 2C, Building 1
Princess Alexandra Hospital
199 Ipswich Rd
Woolloongabba 4102 Qld
Website: https://www.metrosouth.health.qld.gov.au/services/neurology/neurology-princess-alexandra-hospital
Myasthenia gravis is one of the conditions treated at the Princess Alexandra Hospital neurology clinics. The neurology team includes doctors, nurses, occupational therapists, physiotherapists and speech pathologists.
The Neuroimmunology Centre (VIC)
The Royal Melbourne Hospital (RMH) Elizabeth St
Level 7
635 Elizabeth St, Melbourne, Victoria
Email: [email protected]
Phone:(03) 9342 7061
Website:https://www.thermh.org.au/services/neurology-stroke/neurology-stroke-services/multiple-sclerosis-neuroimmunology
The Neuroimmunology clinics are dedicated to the assessment and long-term management of people with a possible or definite diagnosis of MS and other neuroimmunological conditions, including neuromyelitis optica, neurosarcoidosis, autoimmune encephalitis, cerebral vasculitis and myasthenia gravis.
Research and Data
For research updates, please visit Myasthenia Alliance Australia: Research
Please visit Australian Clinical Trials to learn about clinical trials for congenital myasthenic syndromes (CMS) in Australia; there may not be any clinical trials currently available.
Information regarding clinical trials for CMS in other countries can be found at ClinicalTrials.gov; there may not be any clinical trials currently available.
It is best to discuss your interest in any clinical trials with your medical team to determine suitability and eligibility.
Rare Disease Organisation(s)
The Myasthenia Gravis Associations of Australia have come together under a National Myasthenia Alliance to enhance the support already offered to Australians suffering from the neurological auto-immune conditions categorised under the term ‘Myasthenia’, including for congenital myasthenic syndromes (CMS).
Myasthenia Alliance Australia (MAA) RVA Partner Australian Organisation
Website: https://myastheniaalliance.org.au/
Phone: 1800 802 568
Email: [email protected]
Below are the organisations that make up MAA; both organisations provide support for all Australians living with myasthenia, including their families and carers, regardless of location:
Myasthenia Gravis Association of Queensland Inc. RVA Partner Australian Organisation
Website: https://www.mgaq.org.au/
Phone: 1800 802 568
Email: [email protected]
Contact form: https://www.mgaq.org.au/contact-us
The Australian Myasthenic Association in NSW Inc. Australian Organisation
Website: https://www.myasthenia.au/
Phone: (02) 4283 2815
Email: [email protected]
Support Services/Resources
Myasthenia Alliance Australia‘s state organisations provide support resources relevant for individuals living with congenital myasthenic syndromes (CMS):
- Myasthenia Gravis Association of Queensland Inc.: Resources
- Australian Myasthenic Association in NSW: Patient Support
The Loop – Your Neuromuscular Resource Hub: Funding provides information on available social services that are relevant to the neuromuscular community.
For information on available government and social services that provide support for individuals with a rare disease, please visit the National and State Services pages.
Mental Health
Please visit the ‘Mental Health’ sections listed on the National and State Services pages.
Other
Further information on congenital myasthenic syndromes (CMS) or neuromuscular conditions in general can be found at:
References
- Genetic and Rare Diseases (GARD) Information Center. Congenital Myasthenic Syndromes. Accessed 15 March 2023. https://rarediseases.info.nih.gov/diseases/11902/congenital-myasthenic-syndromes/
- National Organization for Rare Diseases (NORD). Congenital Myasthenic Syndromes. Accessed 12 November 2024. https://rarediseases.org/rare-diseases/congenital-myasthenic-syndromes/
- Abicht A, Müller JS, Lochmüller H. Congenital Myasthenic Syndromes Overview. 2003. Updated 23 December 2021. In: Adam MP, Mirzaa GM, Pagon RA, et al. GeneReviews® [internet]. Seattle (WA): University of Washington Seattle. 1993–2024. Accessed 15 March 2023. https://www.ncbi.nlm.nih.gov/books/NBK1168/
- Myasthenia Gravis Association of Queensland Inc. Myasthenia Gravis – a comprehensive guide to living with and understanding this manageable condition. Queensland; 2022. 36p. https://mgaq.org.au/sites/default/files/2024-09/MGAQ_Brochure_2022.pdf
Page Last Updated
19/11/2024 13:25
