Hemoglobin Lepore,,,. in Two Iranian Families

L EPORE HEMOGLOBINS are the result of unequal crossing over between structural genes coding for #{244} and f3 polypeptide chains of human hemoglobin during melosis. The abnormal polypeptide chain #{244} 3 produced after this crossing over has part of the 5 chain at its N terminus, and the remaining part is similar to the i chain.’ The point of fusion of the two polypeptide chains and the proportion ofthe 5 and in the t5jl hybrid chain varies in different types of Lepore hemoglobins. For example, in LeporeHo,,andja crossing over is between residue 22 ofthe 5 chain and residue 50 of the /3 chain2: in LeporeBa,tmor. crossing over has occured between residue 50 of the c5 chain and residue 86 of the /3 chain.’6 In LeporeB0 ,0fl crossing over is somewhere between residue 87 of the t5chain and I I#{244}ofthe f3chain.’2 The inverse of this crossing over results in the synthesis of another polypeptide chain with a 3 chain at its beginning and a #{244} chain at the end (f t5) called anti-Lepore. Hemoglobin Miyada is a good example of an anti-Lepore hemoglobin type in which the f35 crossing over occurred between threonine 12 of the