Myotonic dystrophies are genetic disorders due to autosomal-dominant genetic mutations Genetic Mutations Carcinogenesis and have 2 major clinical forms: myotonic dystrophy type 1 Type 1 Spinal Muscular Atrophy (DM1) and myotonic dystrophy type 2 Type 2 Spinal Muscular Atrophy (DM2). Myotonic dystrophies are heterogeneous diseases primarily affecting the muscles, but, unlike other muscular dystrophies, also have multisystem effects. Both DM1 and DM2 present with myotonia Myotonia Prolonged failure of muscle relaxation after contraction. This may occur after voluntary contractions, muscle percussion, or electrical stimulation of the muscle. Myotonia is a characteristic feature of myotonic disorders. Ion Channel Myopathy, muscle weakness, and myalgias Myalgias Painful sensation in the muscles. Tick-borne Encephalitis Virus; however, DM1 is severe and carries a reduced life expectancy Life expectancy Based on known statistical data, the number of years which any person of a given age may reasonably expected to live. Population Pyramids, whereas DM2 is mild with a normal life expectancy Life expectancy Based on known statistical data, the number of years which any person of a given age may reasonably expected to live. Population Pyramids. Diagnosis is made clinically, with genetic testing, and by electromyography Electromyography Recording of the changes in electric potential of muscle by means of surface or needle electrodes. Becker Muscular Dystrophy (EMG). Management is primarily supportive.
Last updated: 17 Mar, 2022
Myotonic dystrophy is an inherited, autosomal-dominant muscular disease, which causes muscle relaxation incompetence, resulting in progressive muscle wasting Muscle Wasting Duchenne Muscular Dystrophy and weakness.
Both types of myotonic dystrophy cause myotonia Myotonia Prolonged failure of muscle relaxation after contraction. This may occur after voluntary contractions, muscle percussion, or electrical stimulation of the muscle. Myotonia is a characteristic feature of myotonic disorders. Ion Channel Myopathy (sustained muscle contraction) with difficulty or delay in relaxation after use.
Symptoms:
Associated manifestations:
Clinical
presentation
Presentation
The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck.
Normal and Abnormal Labor of 2 adults with myotonic dystrophy
A:
Atrophy
Atrophy
Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes.
Cellular Adaptation of the
forearm
Forearm
The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles.
Forearm: Anatomy and lower
leg
Leg
The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia.
Leg: Anatomy in a patient with DM1
B:
Atrophy
Atrophy
Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes.
Cellular Adaptation is not seen in this patient with DM2, in which symptoms tend to be milder and more proximal.