Polymorphism of SLC14A1 encoding human erythrocytic Kidd antigens in the Chinese population

The SLC14A1 gene, which encodes the important Kidd blood group antigens, has not been systematically?analyzed at the molecular level in Chinese individuals. In this study, SLC14A1 genetic polymorphism was examined in Chinese individuals with Jk(a+b-), Jk(a+b+), and Jk(a-b+) expression. The Kidd phenotype was determined for 146 specimens using monoclonal anti-Jk^a and -Jk^b antibodies. From these, 87 specimens were Jk(a-b+), 21 were Jk(a+b-), and 38 were Jk(a+b+). According to the Kidd phenotype results, 20 specimens were randomly selected from each group, i.e., Jk(a-b+), Jk(a+b-), and Jk(a+b+), for the molecular analyses of exons 3 to 11 of the SLC14A1 gene. Novel alleles were detected in the SLC14A1 gene, including IVS3-106A, IVS3-99A, exon3 130G, IVS4-299G, IVS4-293G, IVS4+211C, IVS4 +230C, exon6 499A, exon6 588A, IVS7-68T, IVS9+244G, and IVS10-153T, indicating that the locus harbored significant polymorphism. We also showed that IVS4-299, IVS7-68, and IVS10-153 were novel SNPs absolutely associated with exon 8 nt. 838. The minor allele frequencies were all greater than 10% and all SNPs in the Chinese population showed Vel antigen expression on RBC membranes. We identified 12 SNPs in the SLC14A1 gene in the Chinese population, IVS3-106A, IVS3-99A, exon3 130G, IVS4-299G, IVS4-293G, IVS4+211C, IVS4 +230C, exon6 499A, exon6 588A, IVS7-68T, IVS9+244G, and IVS10-153T. Our results also indicated that three novel SNPs produced Jk^a and Jk^b antigens in Chinese individuals.     

Genetic variation in Arizona Mexican Americans: estimation and interpretation of admixture proportions

Mexican Americans are a numerous and fast growing ethnic population in the United States. Yet little is known about their genetic structure. Since they are a hybrid, it is of interest to identify their parental populations and to estimate the relative contributions of these groups. This information is relevant to historical, biomedical, and evolutionary concerns. New genetic typings on 730 Arizona Mexican Americans for the HLA-A, HLA-B, ABO, Rh, MNSs, Duffy, Kidd, and Kell loci are presented here and they are used to estimate ancestral contributions. We considered both a dihybrid model with Amerindians and Spaniards as proposed ancestors, and a trihybrid model with Amerindians, Spaniards, and Africans as proposed ancestors. A modified weighted least squares method that allows for linkage disequilibrium was used to estimate ancestral contributions for each model. The following admixture estimates were obtained: Amerindian, 0.29 +/- 0.04; Spaniard, 0.68 +/- 0.05; and African, 0.03 +/- 0.02. The interpretation of these results with respect to Amerindian and Spanish ancestry is straightforward. African ancestry is strongly supported by the presence of a marker of African descent, Fy, despite the fact that the standard error of the estimate is as large as the estimated admixture proportion. An evaluation of the sensitivity of these results to a number of variables is presented: 1) our choices of ancestral allele frequencies, 2) the possibility of selection at HLA and the blood groups, and 3) genetic drift in Mexican Americans.     

国内首次发现两例JK(a—b—)及其在不同人种中的分布

在河南汉族中发现了国内首例稀有的JK(a-b-)红细胞血型。家系调查未发现第二例。先证者父母及同胞均为Jk(a+b-)型,丈夫及儿子均为Jk(a-b+)型。四个月后在广东梅县客家人中又发现一例JK(a-b-)型,先证者为一未婚女子。两位先证者血清中均无抗体。到目前为止,JK(a-b-)型在中国人群中的分布频率为2/6391(0.03％)Jk基因频率为0.0202。     

Molecular genetic analysis of the Kidd blood group system in a Taiwanese family with Jknull phenotype

Two common polymorphisms of 588G/A and 838G/A have been demonstrated in the JK gene, and the latter defines the Jk^a/Jk^b phenotypes. The Jk_null phenotype has been characterized as the absence of Jk^a and Jk^b antigen expression on red cells. We performed a molecular analysis of a family with the Jk_null phenotype and subsequently demonstrated the presence of different JK cDNA haplotypes. In the study, three members of a Jk_null family and 48 randomly-selected individuals were enrolled. The coding exons of the JK gene of the Jk_null family members were amplified by polymerase chain reaction (PCR), and the sequences were analyzed. The genomic region encompassing exons 7~9 of the JK gene was PCR-amplified, cloned, and sequence-determined to elucidate the JK haplotype. We demonstrated that 3 missense mutations, 222C>A, 499A>G and 896G>A were in the JK genes of the Jk_null family members, in addition to the known IVS5–1g>a splice site mutation. Analysis of 48 randomly-selected individuals showed that 499A>G was a common polymorphism, besides 2 Jk_null alleles with respective mutation of 222C>A and 896G>A being demonstrated in the Jk_null family. After compiling the nucleotide information of the polymorphic 499, 588, and 838 positions from the randomly-selected individuals, 5 JK cDNA haplotypes, constituted by the 3 polymorphic sites, were demonstrated. Among these, the JK^a1 (499A, 588G and 838G; 46.9%),JK^b1 (499A, 588G and 838A; 23.9%), and JK^b2(499G, 588G and 838A; 21.9%) were found as the 3 major haplotypes in the Taiwanese population. In conclusion, the Jk_null phenotypes with respective mutations of 222C>A, 896G>A and IVS5–1g>a, were identified in a Taiwanese family. The existence of 5 JK cDNA haplotypes with the 499A/G polymorphism was also demonstrated in the Taiwanese population.     

The frequencies of Kidd blood group antigens and phenotypes among Saudi blood donors in Southwestern Saudi Arabia

BackgroundThe patients who require transfusion are prevalent in the Jazan Province, Saudi Arabia. Therefore, it is essential to know the frequency of blood group antigens in such a population. The Kidd blood group system (JK) has two antithetical antigens, Jk^a and Jk^b. Antibodies to these antigens may result in delayed hemolytic transfusion reactions. The present study investigated the frequencies of Jk^a and Jk^b and the phenotypes among Saudi blood donors living in the Jazan Province.MethodsOne hundred and forty-three samples from anonymous Saudi volunteer blood donors in the Jazan Province were serotype to detect Jk^a and Jk^b using gel card technology and determine the phenotypes of the JK blood group system.ResultsThe prevalence of Jk^a and Jk^b antigens were 90.64% (n = 126) and 69.40% (n = 93), respectively. The JK phenotypes were 34.96% Jk(a + b ? ) (n = 51), 12.59% Jk(a ? b + ) (n = 18), 52.45% Jk(a + b + ) (n = 75), and 0% Jk(a ? b ? ). The frequencies of the JK phenotypes in the Jazan population were significantly different from those in the Asian population (P < 0.05).ConclusionsWe reported the frequencies of the Jk^a and Jk^b antigens and the distribution of the JK phenotypes in a group of Saudi blood donors in the Jazan Province, Saudi Arabia. The phenotype Jk(a + b + ) was the most common among the study population. Furthermore, this study emphasizes the significance of identifying the frequency of JK antigens and phenotypes in the provinces of Saudi Arabia.