The distribution of haptoglobin types in Aichi Prefecture.

Polymorphism of haptoglobin (Hp) types was examined among 2,087 unrelated residents of Aichi Prefecture. The phenotypic distribution obtained agreed well with the genetic hypothesis. The frequency of Hpl gene in Aichi Prefecture was estimated to be 0.247, which is quite similar to those observed in other districts of Japan. 57 A genetically determined polymorphism of haptoglobin (Hp) in human sera was first described by Smithies. I) The three common phenotypes Hp I-I, Hp 2-1 and Hp 2-2 are controlled by a pair of codominant alleles Hpl and Hp2 at an autosomal locus. 2 ) Since the discovery of Hp polymorphism, a great number of papers have been written about the incidence of Hp phenotypes and the estimates of Hp gene frequencies in various populations throughout the world. 3 ) However, no available data concerning the distribution of this polymorphism in Aichi Prefecture have been published yet. This short communication reports the results of our examination on the distribution of Hp types among 2,087 unrelated healthy individuals in this region. Serum samples were collected from the Blood Center of Nagoya Red Cross. The Hp typing was performed by means of horizontal starch gel electrophoresis according to the method of Poulik,4) using a discontinuous system of buffers and 10% Starch-Hydrolysed (Connaught, Toronto, Canada). Electrophoresis was conducted at a constant current of 20 mA/1S cm at 4°C for 2 hours. After the separation, the gel was horizontally sliced and stained with 0.2 % benzidine in 0.5 % acetic acid and 3 % hydrogen peroxide. Table 1. Distribution of Hp types in Aichi Prefecture Phenotype Observed Expected Chi No. % No. % square Hp 1-1 132 6.3 127 6.1 0.197 Hp 2-1 766 36.7 776 37.2 0.129 Hp 2-2 1,189 57.0 1,184 56.7 0.024 Total 2,087 100.0 2,087 100.0 0.350 Gene frequencies; Hpl = 0.247; Hp2 = 0.753 X = 0.350; dJ. = 1; 0.7 > P > 0.5 ~$~., S~ ~, *~~., _* R, .X_D, ~m~­ Received for Publication May 13, 1977 58 H. HATTORI, M. ASANO, M. OVA, O. SUZUKI, Y. KATSUMATA AND S. YADA Table I shows the distribution of Hp types obtained from the present samples. From the data, the gene frequencies of Hpl and Hp2 are estimated as 0.247 and 0.753, respectively. No example of rare phenotypic variants was detected in our samples. The observed numbers are in good agreement with the numbers expected on the basis of Hardy-Weinberg equilibrium (x 2 = 0.350; d.L = I; 0.7> P> 0.5). The value of Hpl gene frequency is identical with the mean value in the Japanese population (Hpl = 0.248).5)