Familial High Density Lipoprotein Deficiency Disease, also known as FHDLD, is a rare genetic disorder that affects the metabolism of high-density lipoproteins (HDL), commonly known as the "good cholesterol". This condition is characterized by extremely low levels of HDL in the bloodstream, which can lead to various cardiovascular complications. Although there are no direct synonyms for FHDLD, it is sometimes referred to as familial HDL deficiency or familial hypoalphalipoproteinemia. These terms highlight the familial nature of the disorder and its impact on the body's lipid profile. It is crucial for individuals with FHDLD to receive proper medical care and lipid-lowering therapies to manage this condition effectively.