Characterization of Jk(a+(weak)): a new blood group phenotype associated with an altered JK*01 allele.

Background: The clinically important Kidd (JK) blood group system is considered to be relatively uncomplicated, both serologically and genetically. The JK*01 and JK*02 alleles give rise to Jk(a) and Jk(b) antigens, respectively, and silenced alleles result in Jk(a-b-). Other inherited variants analogous to Fy(x) and weak D phenotypes have not been characterized for JK, although recent abstracts indicate their presence.

Erythroid urea transporter deficiency due to novel JKnull alleles.

Background: The Kidd blood group antigens Jka and Jkb are encoded by the red blood cell (RBC) urea transporter gene. Homozygosity for silent JK alleles results in the rare Jk(a-b-) phenotype. To date, seven JKnull alleles have been identified, and of these, two are more frequent in the Polynesians and Finns.

Genetic basis of the K(0) phenotype in the Swedish population.

Background: The absence of all Kell blood group antigens (K(0) phenotype) is very rare. K(0) persons, however, can produce clinically significant anti-Ku (K5) after transfusion and/or pregnancy and require K(0) blood for transfusion. Ten alleles giving rise to the K(0) phenotype have been reported: different populations were studied although none from Scandinavia.