A Weak, Inherited, Group A Phenotype

Abstract

Previous examples of a very weak form of the antigen A have been described by Weiner, Sanger and Race (1959) and by Moore, Newstead and Johnson (1961). These phenotypes did not fit the categories of A, (Race, 1957), A,,, (Weiner et al. 1957), or A,, and were left unnamed for future christening. A second family in which a similar phenotype is inheritedapparently as a dominant effectis reported here. ResultsThe family tree is shown in figure 1. L. R. (11-3), the propositus is a healthy blood donor who has never had a transfusion. His sister (11-2) and one son (111-1) have an A antigen with similar characteristics. The other members of the family have blood groups with normal serological properties.(1) Agglutination Tests. (a) The anti-A and anti-A+B sera from stimulated donors that were used to test the cells of J. A. [l] were also

Quantitative Studies of the Phenotype A(el)

“…4) 2 Designation of Sturgeon et al [12] for bloods described by Weiner et al [13] and by Moore et al [6]. …”

Notations for Two Weak A Variants: A(end) and A(el)

“…Moore et al [3,4] reported two similar and probably identical phe notypes in 1961 ; Jacobowicz et al [2] found a further example in 1963. Now that four examples have been reported, in two of which [4,9] the variant was shown to be inherited, to leave this phenotype unnamed is to invite confusion.…”

“…b) Using the same technique, a variable proportion of anti-A from "stimulated donors" produce very weak agglutination [4]. c) Using a centrifugation technique and anti-A or anti-A+B from "stimulated" donors, the majority of the tests show very weak agglutination [3,4]. d) The agglutination produced is distinctive: from 0.5-1% of the cells form small clusters in a sea of unagglutinated cells [3,9].…”

“…The serological characteristics of this phenotype are briefly thus: 1. a) Using a sedimentation technique, no reactions are given by anti-A from donors who have not been injected with group specific substance [3,9]. b) Using the same technique, a variable proportion of anti-A from "stimulated donors" produce very weak agglutination [4]. c) Using a centrifugation technique and anti-A or anti-A+B from "stimulated" donors, the majority of the tests show very weak agglutination [3,4].…”

“…Now that four examples have been reported, in two of which [4,9] the variant was shown to be inherited, to leave this phenotype unnamed is to invite confusion. Therefore a tentative designation is proposed; one which can be changed when the position of this pheno type in the spectrum of A reactivity is clear.…”