“Glycosidic exclusion” does not include the Oh or Bombay Type

The molecular biological relationship between human fertility and the ABO(H) blood group phenotype formation becomes visible through special cell surface structures and immunoglobulin M specificities arising in people with the rare Oh or <i>Bombay</i> blood type, whom Charles Darwin would, by the history of his own family, the “<i>Darwin/Wedgewood Dynasty”</i>, have analyzed to result from reduced fertility in consanguinities. The classical type is characterized by the lack of expression of any ABO(H) epitope and instead shows the development of high isoagglutinin levels, additionally exerting strong binding of complement to anti-H agglutinin. The red cell surface presents with the naked structure Gal-β1-R, which has not been completed for the H-receptor (Fuc-α1-2-Gal-β1-R), thereby representing the structural fundament for ABOH epitopes. In its native form, the <i>Bombay</i> type occurs in individuals with the extremely rare genotype (h/h;se/se). This molecular biological phenomenon is explained by point mutations at the H- and Se genes on chromosome 19 such that the fucosyltransferases FUT1 and FUT2 are not encoded. FUT1 and FUT2 are epistatically connected with the A and B allelic glycotransferase functions encoded on chromosome 9, and fucosyl residues provide the functional-structural basis of the formation of any ABOH phenotype on the cell surface or in secretions and plasma proteins. Moreover, through developmental varying of the positions of the fucosyl residues between the cell surfaces and the heavy chains of immunoglobulins, they appear to augment or reduce antibody-mediated cellular cytotoxicity. This involves the regulation of growth processes and control over physiological autoreactivity in embryonic stem cell to germ cell transformation, where the predominantly <i>O</i>-glycosylations become in <i>Bombay type</i> individuals consequently exposed to metabolic competition with multiple glycosidic sites of extremely glycan depleted immunoglobulins.