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THE group-specific components (Gc) of human sera, described in 1959 by Hirschfeld1, constitute a system of α2-globulins varying in relative electrophoretic mobilities. Family studies disclosed that this system is controlled by two co-dominant autosomal alleles, Gc1 and Gc2 (refs. 2 and 3). Three common phenotypes can be distinguished by immunoelectrophoresis as indicated by the different position and shape of the Gc-precipitates: a fast-moving component (Gc 1–1), and a slow-moving component (Gc 2–2) correspond to the homozygous types; the heterozygous type is characterized by the presence of both components forming an extended, two-peaked precipitate (Gc 2–1). Population surveys have revealed considerable variations in the distribution of Gc allele frequencies in different geographical areas and ethnic groups. The frequencies of Gc2 varied from 0.306 in Indians (Bombay) to 0.023 in a population of Navajo Indians4,5. In the various Jewish populations in Israel the distribution of several genetic traits has been extensively investigated. Differences in the distribution of blood groups6, and incidence of erythrocyte glucose-6-phosphate dehydrogenase deficiency7, have been demonstrated. The differences demonstrated in the distribution of haptoglobins were not statistically significant. Significant differences in the taste sensitivity to phenylthiourea were found only in males. The present investigation is concerned with the distribution of the group specific components among various populations in Israel.

AN erythrocyte glucose-6-phosphate dehydrogenase deficiency has been described among Negroes, non-Ashkenazi Jews and Italians, mostly of Sardinian origin1–3. This enzymatic abnormality is known to be associated with an increased susceptibility to haemolysis following ingestion of a number of drugs as well as of fava beans4,5, and appears to be transmitted as a sex-linked incompletely dominant trait6.

THE interest in the patterns of haptoglobin types has been furthered during the past several years due to the introduction of starch-gel electrophoresis for their demonstration1. Different populations have been investigated up to now2,3.

DURING our screening for haptoglobin patterns in different Jewish ethnic groups1,2, we found a sample from a Kurdish boy (from Urmia in the Kurdish part of Persia) which appeared to contain a ‘Johnson type of haptoglobin pattern’3. (We thank Prof. H. Harris (London) for comparing it with a known sample and identifying it.) Further examination of the family revealed the following results (Figs. 1 and 2). The mother of the propositus had a Johnson pattern of Hp and the father a Hp2–1 pattern; of the 7 children two had Johnson type Hp, one Hp1–1, one Hp2–1, two ‘ahaptoglobinaemia’ and one a hypohaptoglobinaemia. Two-and-a-half-fold concentration of the two ahaptoglobinaemic and the hypohaptoglobinaemic sera revealed the presence of haptoglobin in all of them. However, the exact pattern in them could not be determined.