Myotonic Muscular Dystrophy (MMD) (Also known as Steinert Disease, dystrophia m
Definition - One of nine types of muscular dystrophy, a group of genetic, degenerative diseases primarily affecting voluntary muscles.
Cause - A repeated section of DNA on either chromosome 19 or chromosome 3.
Onset - Congenital form appears at birth. More common form may begin in teen or adult years.
Symptoms - Generalized weakness and muscle wasting first affecting the face, lower legs, forearms, hands and neck, with delayed relaxation of muscles after contraction common. Other symptoms involve the gastrointestinal system, vision, heart or respiration. Learning disabilities occur in some cases. Congenital myotonic dystrophy is the more severe form.
Progression - Progression is slow, sometimes spanning 50 to 60 years.
Inheritance - Autosomal dominant; the disease may be inherited through either the father or the mother.