Muscular dystrophy is a progressive sex-linked disease affecting men more often than women that eventually leads to complete muscular collapse and most often has manifestations in organs, including heart, liver, nervous system and lungs.
First documented in the 1860s, Dr. Guillaume Duchenne gave an account of boys who grew progressively weaker, losing the ability to walk, and died at an early age. Duchenen's name was given to this type of muscular dystrophy (MD). Later it was recognized that there are many forms of MD, including Becker, limb girdle, congenital and myotonic, among others, and that MD affects women but at a lesser rate because MD is transmitted on the X chromosome, thereby qualifying it as a sex-linked disease.
Transmission in women requires the mutated gene be present in both the X chromosomes, whereas transmission in men, who have only one X chromosome that is paired with one Y chromosome, requires the mutated gene be present only on the X chromosome, thereby increasing incidence of MD in men.