A familial syndrome with hypo-alpha-lipoproteinemia is described. The affected propositus and his relatives have low levels of high density lipoprotein-cholesterol and apolipoprotein A, without any other lipid and lipoprotein abnormalities. Lipase activity and lecithin:cholesterol acyltransferase activity are also normal. A high prevalence of premature cardiac events was observed in this kindred, without any other established coronary risk factors present. The longevity analyses showed a shortening of life expectancy. The biochemical data and the pedigree are compatible with an autosomal dominant mode of inheritance.