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.
Most of the known causes of congenital heart disease are sporadic genetic changes, either focal mutations or deletion or addition of segments of DNA. Large chromosomal abnormalities such as trisomies 21, 13, and 18 cause about 5â8% of cases of CHD, with trisomy 21 being the most common genetic cause.