Gastrointestinal issues can result, which can be severe, manifestations including diarrhea, constipation, and fecal incontinence. The symptoms of adult DM often manifest during adolescence. Infantile DM1 can be distinguished as another disease category, or it can be grouped with congenital DM1 or childhood-onset DM1. Childhood-onset DM1
Childhood-onset DM1 is defined as onset of symptoms between ages 1 and 10 years. Manifestations include the same intellectual and gastrointestinal symptoms seen in congenital DM1. DM2
DM2 is generally milder than DM1, with generally fewer DM2 people requiring assistive devices than DM1 people. DM2 preferentially affects muscles closer to or on the torso, including the neck flexors, hip flexors, and hip extensors. Muscle pain is prominent in DM2. Heart issues, while still potentially fatal, are less common and severe in DM2 than DM1. Symptoms onset in early to late adulthood. Severe congenital onset, which can occur in DM1, has not been observed in DM2. Genetics
Myotonic dystrophy (DM) is a genetic condition that is inherited in an autosomal dominant pattern, meaning each child of an affected individual has a 50% chance of inheriting the disease. The mutation involves satellite DNA, which is tandemly repeated sequences of DNA that do not code for a protein. The repeats implicated in myotonic dystrophy are either 3 or 4 nucleotides in length, classified as microsatellites. Disease results from an abnormally increased number of these microsatellites, termed microsatellite expansion. DM1
The microsatellite expansion responsible for DM1 is of cytosine-thymine-guanine (CTG) triplet repeats, termed trinucleotide repeat expansion and classifying DM1 as a one of several trinucleotide repeat disorders.
Myotonic dystrophy (DM) is a type of muscular dystrophy, a group of genetic disorders that cause progressive muscle loss and weakness. In DM, muscles are often unable to relax after contraction. Other manifestations may include cataracts, intellectual disability and heart conduction problems. In men, there may be early balding and an inability to have children. While myotonic dystrophy can occur at any age, onset is typically in the 20s and 30s.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). DM is typically inherited from a persons parents, following an autosomal dominant inheritance pattern, and it generally worsens with each generation. A type of DM1 may be apparent at birth. DM2 is generally milder. Diagnosis is confirmed by genetic testing.There is no cure. Treatments may include braces or wheelchairs, pacemakers and non-invasive positive pressure ventilation. The medications mexiletine or carbamazepine can help relax muscles. Pain, if it occurs, may be treated with tricyclic antidepressants and nonsteroidal anti-inflammatory drugs (NSAIDs).Myotonic dystrophy affects more than 1 in 8,000 people worldwide. It is the most common form of muscular dystrophy that begins in adulthood. It was first described in 1909, with the underlying cause of type 1 determined in 1992. Signs and symptoms
DM causes muscle weakness, early onset of cataracts, and myotonia, which is delayed relaxation of muscles after contraction.