Erythroid urea transporter deficiency due to novel JK(null) alleles
BACKGROUND: The Kidd blood group antigens Jk(a) and Jk(b) 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 JK(null) alleles have been identified, and of these, two are more frequent in the Polynesians and Finns. This study reports the identification of other JK(null) alleles in Jk(a-b-) individu