What is (are) familial HDL deficiency ?
Familial HDL deficiency is a condition characterized by low levels of high-density lipoprotein (HDL) in the blood. HDL is a molecule that transports cholesterol and certain fats called phospholipids through the bloodstream from the body's tissues to the liver. Once in the liver, cholesterol and phospholipids are redistributed to other tissues or removed from the body. HDL is often referred to as "good cholesterol" because high levels of this substance reduce the chances of developing heart and blood vessel (cardiovascular) disease. People with familial HDL deficiency may develop cardiovascular disease at a relatively young age, often before age 50.  Severely reduced levels of HDL in the blood is a characteristic feature of a related disorder called Tangier disease. People with Tangier disease have additional signs and symptoms, such as disturbances in nerve function; enlarged, orange-colored tonsils; and clouding of the clear covering of the eye (corneal clouding). However, people with familial HDL deficiency do not have these additional features.