June Gavin

The Red Cell Phenotype En(a‐) and Anti‐Ena: Serological and Physicochemical Aspects

Summary. The lack of the very common red cell antigen Ena is a rare recessive character. En(a‐) cells are further unusual in having only about 33% of the normal amount of sialic acid and in having an electrophoretic mobility about 60% of normal. These abnormalities adequately explain other peculiarities of En(a‐) cells: their weak MN antigens, their ability to be agglutinated, though suspended in saline, by appropriate incomplete Rh antisera, and their preferential agglutination by certain seed extracts and non‐immune animal sera.

Persistent Mixed Field Polyagglutinability

Abstract. The red cells of a 28‐year‐old healthy group O donor, Mr. O.S. (OS‐cells), have persisted, over 4 years of investigation, in showing mixed field polyagglutinability. About 50% of the red cells are agglutinated by the great majority of human sera from adults, by some seed and snail extracts and by the serum of various animals. The cells further show a certain affinity for anti‐A reagents which can be distinguished from that of true A cells. The sialic acid content of the polyagglutinable fraction of the cells is decreased with consequent reduction in their electrophoretic mobility. Inhibition tests show that the disturbance involves n‐acetyl‐d‐galactosamine.

Xg groups and sex chromosome abnormalities in people of northern European ancestry: an addendum.

A catalogue of the Xg groups of 1547 patients with various abnormalities of number or of form of their sex chromosomes, together with the groups of many of their parents, appeared in this journal in 1971 (Sanger et al., 197 1a). All the Xg tests were done in the MRC Blood Group Unit and covered the time from the recognition of the Xg groups (Mann et al., 1962) to January 1971. The results were given in 8 tables. The purpose of the present communication is to record that the count was brought up to October 1975 by the addition of 536 more patients and that the revised 8 tables are available on request. The tables give the totals and analysis of the Xg groups of the following classes of propositi and their available parents: Table 1, 739 propositi with Klinefelters syndrome; Table 2, parents of 566 XXY propositi; Table 3, 56 XX male propositi and their parents; Table 4, 975 propositi with Turners syndrome; Table 5, parents of 610 of the Turner propositi; Table 6, 313 propositi with other kinds of sex chromosome abnormalities; Table 7 parents of 29 females with one X lacking a long arm; Table 8, normality of the Xg distribution in both parents of 647 assorted propositi. Here follow only a few notes prompted by the increased numbers. The Xg phenotype frequencies for normal northern Europeans are: for males Xg(a+) 0-659 and Xg(a-) 0 341; and for females Xg(a+) 0-884 and Xg(a-) 0 1 16 (Sanger et al., 1971b).

Xg groups and sex abnormalities in people of northern European ancestry.

This paper presents a succession of tables with little comment. We are from time to time asked for the latest Xg score in certain categories of sex chromosome abnormalities and so hope some of the tables may be useful. The X-linked Xg blood group system was recognized late in 1961 (Mann et al, 1962). An account of its application, in the Blood Group Unit, to certain sex chromosome abnormalities in people of northern European extraction from that time until the end of April 1968 was given in the British Medical Bulletin (Race and Sanger, 1969). This present paper brings our account up to 7 January 1971, and includes some conditions not summarized in the 1969 account. Many of the cases out of which the tables are built have been published, so the present list should not be pooled with any previous publication in which the Xg groups were done by the Blood Group Unit.

The red cell antigen Pk and its relationship to the P system: the evidence of three more Pk families.

The results of testing the families of the third, fourth and fifth Pk propositi have advanced the understanding of this antigen and its relationship to the P system.

FAMILIAL SIDEROBLASTIC ANÆMIA: PROBLEM OF Xg AND X CHROMOSOME INACTIVATION

Abstract A moderately severe sideroblastic anaemia with a dimorphic red-blood-cell population was found in a Liverpool girl. Similar morphological changes in the red blood-cells without anaemia were found in two of her sisters, mother and maternal grandmother. Separation of the red-blood-cell populations on the basis of morphology did not provide evidence that the locus for the Xg blood-group is subject to inactivation, and this contrasts with the findings in a previous report.

A New Anti‐Erythrocyte Antibody in the Duffy System: Anti‐Fy4

Abstract. A new Duffy antibody, designated anti‐Fy4, was found to react with all samples of type Fy(a‐b‐), some of type Fy(a‐b+) and Fy(a+b‐), and none of type Fy(a+b+).

Mk and Mg: some serological and physicochemical observations.

Knowing the difficulty of filing blood group information we thought it might be found convenient if, from the work on the En blood groups reported earlier in this Issue [2], were separated some observations concerning cells heterozygous for the Mk and Mg alleles of the MN system [3, 1, 41. During the En investigation, the opportunity arose to test samples of red cells from a family in which Mk was segregating (kindly sent by Dr. P. STURGEON). The M k samples though suspended in saline were agglutinated by incomplete Rh antisera corresponding to their Rh groups; the strength of the reaction was about that given by En(a+) heterozygous (EnaEn) cells [2]. This parallel with En led to the testing of M k cells with an extract of seeds of Sophora japonica (from which the anti-A+B had been removed): again the M k cells were agglutinated about as strongly as were EnaEn cells. Furthermore, Mk cells, like EnaEn cells, appear to have more H antigen than do appropriate controls. Samples of blood from Mk heterozygotes and from controls were then sent from Zurich to Helsinki for measurement of electrophoretic mobility and sialic acid content. Again the M k cells behaved like En

Failure to detect linkage between Xg and other X‐borne loci in Sardinians

A genetical survey of the population of Sardinia with particular emphasis on the X-linked characters glucose-6-phosphate dehydrogcnase (G-6-PD) and colour vision had been going on for 3 years (Siniscalco, Rernini and Latte 1961 ; Siniscalco, 1963) when the recognition of the X-linked blood group, Xg, was reported (Mann et al. 1962). In the spring of 1962 this new marker was brought into the survey and the present report gives the account of the Xg-linkage work in Sardinia up to the spring of 1965. The work fell into four series: spring 1962, autumn 1962, 1964 and 1905. During the progress of the Sardinian investigation a series of Israeli families was tested for G-6-PD and for Xg (Adam et al. 1963 ; Sanger & Adam, 1964). The results gave significant indication of measurable linkage between Xg and G-6-PD and the most likely estimate of the recombination fraction, 8, was 0.26. However, the 90 yo confidence limits were wide : 0.15 and 0.43. Then a serics of Greek families was tested for G-6-PD and for Xg, and, although the results wwe probably not significant in themselves, again the best estimate of 8 was 0.26 and the 90 yo confidence limits werc: 0.13 and 0.47 (Fraser et al. 1964). The Israeli and the Greek results when combined were highly significant of measurable linkage (0 = 0.26, 90 pcr cent confidence limits = 0.17 and 0.40) but the Sardinian families which were by then mounting up showed no sign of the recombination fraction being as low as 0.26 nor, indeed, any hopeful sign of the two genes being within measurable distance of each other (Siniscalco, 1964). Thoughts were then turned to the possibility that the discrepant results in Sardinia might be due to an X chromosome inversion perhaps common in those people (Filippi, Latte, Piomelli, Race, Rattazzi and Siniscalro, 1965); but a t the same time a second survcy in Israel was organized, again in collaboration with Dr Sheba and Dr Adam. This second survey is confined to three-generation families and at its present stage is not showing the linkage shown by the first survey: as a consequer ce the idea of an inversion common in Sardinia has, for the present, been shelved. As the first Israeli series were mostly two-generation families their analysis was dependent on statistical tests.

The X-linked Blood Group System Xg: More Tests on Unrelated People and on Families

Tests with anti‐Xga on 419 unrelated Caucasians, mostly British, are here reported: they bring the total tested in the Blood Group Research Unit up to 1008. Of 517 males 62.9 per cent were Xg(a +) and of 491 females 89.4 per cent were Xg (a+): the gene frequencies derived therefrom are Xga 0.651 and Xg 0.349.