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A dispermic chimera was identified in a healthy man with mixed field agglutination reaction in ABO blood grouping and mosaic 46, XY/46, XX karyotype

BACKGROUND Chimerism is the presence of two or more genetically distinct cell populations in one organism. Here, we reported the identification of dispermic chimerism in a 25-year-old male. METHODS Blood grouping was performed with standard gel centrifugation test cards. ABO and HLA-A,-B,-C,-DRB1 and -DQB1 loci genotyping was determined with PCR sequence-based typing. A quantitative analysis of dual red cells populations was measured by flow cytometer. The karyotype was analyzed by G-banded chromosomes. Short tandem repeat (STR) analysis was performed on blood, buccal mucosal and hair shafts samples. RESULTS A mixed-field agglutination with anti-B antibody was observed with gel centrifugation tests, which showed a double populations of O and B groups RBCs. Two groups RBCs were also observed by flow cytometer with nearly 90% O group cells and 10% B group cells. The normal O01,O02,B101 alleles were identified in DNA sample of the proband. STR analysis revealed three alleles for D8S1179,D3S1358,TH01,D13S317,D16S539,D2S1338,D19S433,TPOX and D18S51 loci. HLA-DRB1 and -DQB1 loci had three alleles and a karyotypic mosaic was found with 60% 46, XY and 40% 46, XX karyotype in the proband. In all studies, the third allele was attributable to a dual paternal contribution. CONCLUSION A individual with dispermic chimerism was identified, which would generate by fertilization of an oocyte and the corresponding second polar body by two different sperms.

Serological characteristic and molecular basis of A2 subgroup in the Chinese population

BACKGROUND A2 phenotype is a common subgroup of blood group A, but the serological characteristic and genetics basis of A2 phenotype currently was rare reported in the Chinese Han population. Here, a large scale study of the serology and genetics of A2 and A2B phenotypes was performed. METHODS/MATERIALS 11263 Chinese individuals with group A and AB phenotypes were determined for A2 antigen with the standard serological method. The full coding region of the ABO gene was sequenced in the individuals with A2 and A2B phenotypes. Some samples including each ABO genotypes were chosen for determining the activity of glycosyltransferase A (GTA) in plasma. RESULTS 134 individuals were assigned as A2 and A2B phenotypes in 11263 individuals. There was imbalance in A2 and A2B phenotypes and the proportion of A2B among AB samples was significantly higher than that of A2 in group A samples. All samples of the A2 and A2B phenotypes were classified into A2-related allele group, A1-related allele group and the other group based on kind of the ABO genotype. Four novel A2-related alleles (A217, A218, A219, A220) were identified. The individuals with same genotype showed different agglutination strength with anti-A1 and anti-H on their RBCs. The plasma from individuals with A2-related allele had almost no GTA activity, while plasma from individuals with A1-related allele had some GTA activity. CONCLUSION A2 and A2B phenotypes could derive from different genotypes and the serological characteristic may be heterogeneity in the Chinese Han population.

Identification of a novel B allele with missense mutation (c.98G > C) in the ABO gene

A BO is considered one of the most clinically relevant blood group systems in both transfusion and transplantation medicine. Since the discovery of the ABO gene, several hundred variant alleles resulting in subtypes have been characterized and reported in the Blood Group Antigen Gene Mutation Database. In this report, we present a novel missense mutation (c.98G>C) in Exon 2 of the ABO gene with a B subtype that has been identified in a Chinese individual.

Molecular basis for the p and Pk phenotypes in three Chinese individuals

Dear Sir, There are two rare null phenotypes, Pk and p, in which P and P/Pk/P1 antigens are lacking, respectively. It has been reported that the α1,4-galactosyltransferase gene (A4GALT) encodes an enzyme for the synthesis of both Pk and P1 antigens (Furukawa et al., 2000; Steffensen et al., 2000; Thuresson et al., 2011), while the β1,3-N-acetylgalactosaminyltransferase gene (B3GALNT1) makes the P antigen (Okajima et al., 2000). Until now, the molecular bases of the p and Pk phenotypes have been analysed in a number of individuals of various ethnic origins, and more than 23 mutations for A4GALT with p phenotype and 8 mutations for B3GALNT1 with Pk phenotype have been described and included in the dbRBC of NCBI (Blumenfeld & Patnaik, 2004). We previously reported a novel A4GALT allele in a Chinese individual with p phenotype (Yan et al., 2004). Here, we describe the molecular mechanisms underlying two individuals with p phenotype and one individual with suspected Pk phenotype in China. Two unrelated blood donors with p phenotype were identified. One Chinese individual was identified to have the Pk phenotype. The ethnicity of them were Han, and all samples were collected after obtaining informed consent. Monoclonal anti-P1 reagent (Immucor Inc., Houston, TX, USA), human anti-PP1Pk from our previous study (Yan et al., 2004) and human anti-Pk were used for detecting the blood group antigens of these individuals. The 2195 or 1705 bp length fragments spanning the full coding region of the A4GALT or B3GALNT1 were amplified by polymerase chain reaction (PCR) with pF2 (5′TTTAGTGGG TTCCAGCGTCC3′) and pR1 (5′ATCCTTC CTGCCTGTTG TCT3′) primers pair or B3GT1-F1 (5′TATCCC ACATCA GCAGTCAC3′) and B3GT1-R1 (5′CAGTTCAGTGTAAGCCA GCA3′) primers pair, respectively. The PCR reaction mixture (25 μL) contained 1× PCR buffer (TaKaRa, Dalian, China), 200 μmol L−1 of each dNTP (TaKaRa), 0·5 μmol L−1 of each specific primer, 1·50 mmol L−1 MgCl2, 1·0 U LA Taq DNA polymerase (TaKaRa) and about 100 ng genomic DNA. The PCR reaction conditions for A4GALT or B3GALNT1 was 95 ◦C for 3 min followed by 35 cycles of 30 s at 94 ◦C, 30 s at 64 ◦C (67 ◦C for B3GALNT1) and 150 s (120 s for B3GALNT1) at 72 ◦C, plus a final extension at 72 ◦C for

A novel mutation +5904 C>T of RUNX1 site in the erythroid cell-specific regulatory element decreases the ABO antigen expression in Chinese population

An erythroid cell‐specific regulatory element (+5·8‐kb) in the first intron of ABO is responsible for the antigen differential expression and the regulatory activity of the element was affected by the nucleotide mutation in the +5·8‐kb region. Currently, many individuals with ABO subgroups were found in the Chinese population, but there was little information about the function of +5·8‐kb region in these individuals. Here, we studied the mechanism of the mutation in the +5·8‐kb region responsible for reducing of antigen expression in 30 ABO subtype Chinese individuals without mutation in the coding region or splicing site.

c.49T>C mutation on the α-(1,2)-fucosyltransferase gene responsible for an individual with para-Bombay phenotype: MUTATION ON THE α-(1,2)-FUCOSYLTRANSFERASE GENE

T he H blood group phenotype is uniquely dependent on the expression of a-(1, 2)-fucosyltransferase enzyme, the product of FUT1 gene. The Bombay and para-Bombay phenotypes in the H blood group are characterized by the deficiency of H blood group antigens on red blood cells (RBCs). It was proved that the inactive alleles of the FUT1 will affect the H antigen expression on RBCs and result in the Bombay and para-Bombay phenotypes. Currently, more than 55 silencing or weakening mutations of FUT1 have been described in the dbRBC of NCBI. Here, we report a novel mutation c.49T>C of FUT1 that was identified in an individual with paraBombay phenotype in China.