What is myotonic dystrophy?
Myotonic dystrophy is the most common form of adult-onset muscular dystrophy, with a worldwide prevalence of 14 per 100,000 population and 189 per 100,000 population in Saguenay-Lac-Saint-Jean region of Quebec. Myotonic dystrophy is an autosomal dominant disorder caused by an error in genes located on chromosome 19 or chromosome 3.
There are two types of myotonic dystrophy:
- Type 1, also known as Steinert’s disease
- Type 2, also known as proximal myotonic myopathy (PROMM) – is caused by a mutation in the CNBP gene. This type is only found in adults, with an age of onset generally between 30 and 60 years.
- myotonia that results in a delay in the ability to relax the muscles after a prolonged contraction
- voluntary muscle weakness
- muscle stiffness
- drooping eyelids
- unclear word pronunciation
- difficulty raising the head when lying down
- difficulty holding an object firmly
- a shuffling gait
- difficulty climbing stairs or rising from a seated position
Dr. Maurice Swanson
Presenter: Maurice Swanson, MD
Description: In this YouTube video, Dr. Swanson provides an overview of myotonic dystrophy.
Dr. Jack Puymirat
Presenter: Jack Puymirat, MD, PhD, CHU Quebec
Description: Dr. Puymirat describes his work and whether progress is made toward a gene therapy for myotonic dystrophy.
Patients with myotonic dystrophy – See Chapter 11 (pages 132-137)