 As a major component of the high-density lipoprotein complex (protective "fat removal" particles), apo A1 helps to clear fats, including cholesterol, from white blood cells within artery walls, making the WBCs less likely to become fat overloaded, transform into foam cells, die and contribute to progressive atheroma.Five of nine men found to carry a mutation (E164X) who were at least 35 years of age had developed premature coronary artery disease.One of four mutants of apo A1 is present in roughly 0.3% of the Japanese population, but is found in 6% of those with low HDL cholesterol levels.