| Myotonic dystrophy | |
|---|---|
| Other names | Dystrophia myotonica,[1] myotonia atrophica,[1] myotonia dystrophica,[1] Curschmann–Batten–Steinert syndrome |
 | |
| Areas of body affected in myotonic dystrophy, types 1 and 2, colored in red | |
| Specialty | Neurology, neuromuscular medicine, physical medicine and rehabilitation, medical genetics, pediatrics |
| Symptoms | Muscle loss, weakness, muscles which myotonia[1] |
| Complications | Cataracts, intellectual disability, heart conduction problems[1][2] |
| Usual onset | 20s to 30s[1] |
| Duration | Long term[1] |
| Types | Type 1, type 2[1] |
| Causes | Genetic disorder (autosomal dominant)[1] |
| Diagnostic method | Genetic testing.[2] |
| Treatment | Braces, wheelchair, pacemakers, non invasive positive pressure ventilation[2] |
| Medication | Mexiletine, carbamazepine, tricyclic antidepressants, nonsteroidal anti inflammatory drugs[2] |
| Frequency | >1 in 8,000 people[1] |
Myotonic dystrophy (DM) is a type of muscular dystrophy, a group of genetic disorders that cause progressive muscle loss and weakness.[1] In DM, muscles are often unable to relax after contraction.[1] Other manifestations may include cataracts, intellectual disability and heart conduction problems.[1][2] In men, there may be early balding and infertility.[1] While myotonic dystrophy can occur at any age, onset is typically in the 20s and 30s.[1]
Myotonic dystrophy is caused by a genetic mutation in one of two genes. Mutation of the DMPK gene causes myotonic dystrophy type 1 (DM1). Mutation of CNBP gene causes type 2 (DM2).[1] DM is typically inherited, following an autosomal dominant inheritance pattern,[1] and it generally worsens with each generation.[1] A type of DM1 may be apparent at birth.[1] DM2 is generally milder.[1] Diagnosis is confirmed by genetic testing.[2]
There is no cure.[3] Treatments may include braces or wheelchairs, pacemakers and non-invasive positive pressure ventilation.[2] The medications mexiletine or carbamazepine can help relax muscles.[2] Pain, if it occurs, may be treated with tricyclic antidepressants and nonsteroidal anti-inflammatory drugs (NSAIDs).[2]
Myotonic dystrophy affects about 1 in 2,100 people,[4] a number that was long estimated to be much lower (often cited as 1 in 8,000), reflecting that not all patients have immediate symptoms and, once they do have symptoms, the long time it typically takes to get to the right diagnosis.[1] It is the most common form of muscular dystrophy that begins in adulthood.[1] It was first described in 1909, with the underlying cause of type 1 determined in 1992.[2]
- ^ a b c d e f g h i j k l m n o p q r s t u v "myotonic dystrophy". GHR. 11 October 2016. Archived from the original on 18 October 2016. Retrieved 16 October 2016.
- ^ a b c d e f g h i j Meola, G; Cardani, R (April 2015). "Myotonic dystrophies: An update on clinical aspects, genetic, pathology, and molecular pathomechanisms". Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 1852 (4): 594–606. doi:10.1016/j.bbadis.2014.05.019. PMID 24882752.
- ^ Klein, AF; Dastidar, S; Furling, D; Chuah, MK (2015). "Therapeutic Approaches for Dominant Muscle Diseases: Highlight on Myotonic Dystrophy". Current Gene Therapy. 15 (4): 329–37. doi:10.2174/1566523215666150630120537. PMID 26122101.
- ^ Johnson, N. (2021). "Population-Based Prevalence of Myotonic Dystrophy Type 1 Using Genetic Analysis of Statewide Blood Screening Program". Neurology. 96 (7): e1045–e1053. doi:10.1212/WNL.0000000000011425. PMC 8055332. PMID 33472919.