Apolipoprotein deficiencies are genetic disorders that affect the proteins responsible for transporting lipids, such as cholesterol and triglycerides, in the bloodstream. These proteins, known as apolipoproteins, play a crucial role in lipid metabolism and help maintain healthy levels of fats in the body. When there is a deficiency, it can lead to abnormal lipid levels, increasing the risk of cardiovascular diseases. Common types of apolipoprotein deficiencies include Apolipoprotein A-I deficiency and Apolipoprotein E deficiency. Symptoms may vary but can include fatty deposits in the skin or eyes, liver problems, and an increased risk of heart disease. Diagnosis typically involves blood tests to measure lipid levels and genetic testing to identify specific deficiencies.