A: The function of the cartilaginous rings of the trachea is to stabilize the trachea and keep it rigid while allowing the trachea to expand and lengthen when the person breathes. If the trachea was not supported in this way, it would simply collapse because of the pressure of the chest.
HCM remains the most common cardiovascular genetic disorder, occurring in at least 1 in 500 people in the general population. 7 HCM is a primary inherited disorder of the myocardium characterized by hypertrophy, usually of the left ventricle, in the absence of other loading conditions such as hypertension.
and some types affect cardiac muscle. Duchenne MD. is the most common childhood form of MD, as well as the most common of the muscular dystrophies overall, accounting for approximately 50 percent of all cases. Because inheritance is X-linked recessive (caused by a mutation on the X, or sex, chromosome), Duchenne MD primarily affects boys, although girls and women who carry the defective gene may show some symptoms. About one-third of the cases reflect new mutations and the rest run in families. Sisters of boys with Duchenne MD have a 50 percent chance of carrying the defective gene. Duchenne MD usually becomes apparent during