Genetic studies of human apolipoproteins. I. Polymorphism of apolipoprotein A-IV.

Genetic polymorphism of human apolipoprotein A-IV has been detected by means of a simple and rapid one-dimensional isoelectric-focusing technique followed by immunoblotting. In plasma samples of normal U.S. whites and blacks, the specificity and sensitivity of the technique have been demonstrated to elucidate biochemical and genetic variation present in the APO A-IV molecule. Two common alleles, APO A-IV 1 and APO A-IV 2, have been observed with respective frequencies of .909 and .088 in whites and .961 and .035 in blacks. In addition, the products of two rare alleles designated APO A-IV 3 and APO A-IV 4 also have been observed. Family studies show autosomal codominant transmission of four alleles coded by a single structural locus.