Blood Group, Kidd System

A number sign (#) is used with this entry because the antigens of the Kidd blood group system are encoded by the SLC14A1 gene (613868) on chromosome 18q12.3.

Description

The Kidd blood group locus encodes a urea transporter (SLC14A1) that is expressed on human red cells and in the kidney. The Kidd blood group system (Jk) is defined by 2 alleles, Jk(a) and Jk(b), whose products were first identified with alloantibodies responsible for haemolytic disease of the newborn or transfusion reactions (summary by Olives et al., 1997).

Clinical Features

Although Jk-null red blood cells have reduced urea permeability, the Jk deficiency is not associated with any obvious clinical syndrome except for a urine concentration defect (Sands et al., 1992) that probably results from the absence of the Jk protein expressed on endothelial cells of the vasa recta of kidney (Xu et al., 1997; Promeneur et al., 1996). Persons with the Jk-null phenotype are detected because antibody against Jk3 can develop after immunization by transfusion or pregnancy, and this antibody may cause immediate and delayed hemolytic transfusion reactions (Lucien et al. (2002)).

Mapping

HGM9 concluded provisionally that the Jk locus is at 18q11-q12 (Geitvik et al., 1987). The L2.7 probe used in the assignment to chromosome 18 was thought to lie on the short arm, close to the centromere. The maximum lod score was 8.53 at recombination fraction of 0.03 (upper probability limit 0.11). Geitvik et al. (1987) quoted deletion data excluding Jk from a considerable part of chromosome 18 and contributing to the assignment of 18q11-q12.

The Kidd blood group had been assigned to 18p by linkage to a polymorphic anonymous DNA probe, L2.7 (Gedde-Dahl, 1986). Leppert et al. (1987) also found linkage of blood group Kidd to 2 DNA markers on chromosome 18; the maximum lod scores were 3.61 at theta = 0.168 and 4.18 at theta = 0.218.

Gross (2016) mapped the SLC14A1 gene, which encodes the antigens of the Kidd blood group system, to chromosome 18q12.3 based on an alignment of the SLC14A1 sequence (GenBank BC050539) with the genomic sequence (GRCh38).

Molecular Genetics

Olives et al. (1997) determined the genetic basis for the Kidd blood group polymorphism by sequencing reverse-transcribed reticulocyte RNAs from Jk(a+b-) and Jk(a-b+) donors. They found that the difference between Jk(a) and Jk(b) was a G-to-A transition at nucleotide 838, resulting in an asp280-to-asn amino acid substitution (613868.0001) and an MnlI RFLP.

History

On the basis of studies of a patient with deletion of part of the long arm of chromosome 7, Shokeir et al. (1973) proposed that the Kidd blood group is on the deleted segment. The parents were homozygous Jk(a) and Jk(b) and all 9 sibs of the proband were heterozygous as one would expect. The proband herself was Jk(a). Hulten et al. (1966) previously suggested that the Kidd locus is on either chromosome 2 or a C group chromosome, but banding techniques were not then available.

Mace and Robson (1974) found a hint of linkage between 'red-cell' acid phosphatase (171500), which is coded by chromosome 2, and Kidd blood group. Mohr and Eiberg (1977) found a lod score of plus 2.57 for the linkage of Kidd and Colton. Each had been tentatively assigned to chromosome 7.

Under 3 different genetic models for IDDM, Hodge et al. (1981) found evidence for linkage with 2 different sets of marker loci: HLA (see 142800), properdin factor B (138470), and glyoxalase-1 (138750) on chromosome 6, and Kidd blood group on chromosome 2. The 71 families studied apparently did not fall into 2 groups, one exhibiting linkage to HLA and the other to Kidd. Thus, they concluded that at least 2 distinct disease-susceptibility loci may be involved in IDDM, a situation also postulated for Graves disease (275000). (The Jk blood group is encoded by a solute carrier gene on chromosome 18q11-q12; an IDDM locus, IDDM6 (601941), maps to 18q21.)

Field et al. (1985) and Sherman and Simpson (1985) provided evidence for linkage of IGK (147200) and Jk and, therefore, assignment to chromosome 2. This suggested that the Colton blood group locus (110450) may also be on chromosome 2. Sherman and Simpson (1985) published a collated maximum lod score of 3.14 at theta 0.31 for Jk:IGK.

Pausch and Mayr (1987) presented additional data supporting linkage of Jk and IGK. Together with the data of Field et al. (1985), the maximum lod score reached 3.0 for theta = 0.32.