Serological characteristics and molecular mechanism of an individual with p phenotype / 中华医学遗传学杂志

OBJECTIVE@#To analyze the serological characteristics and molecular mechanism for an individual with p phenotype.@*METHODS@#An individual with p phenotype upon blood group identification at Jiaxing Blood Center in May 2021 was analyzed. ABO, RhD and P1PK blood groups and irregular antibodies in her serum were identified using conventional serological methods. The encoding region of α1, 4-galactosyltransferase gene (A4GALT) encoding P1 and Pk antigens was analyzed by polymerase chain reaction-sequence-based typing (PCR-SBT).@*RESULTS@#The individual was A group, RhD positive and had a p phenotype of the P1PK blood group system. Anti-PP1Pk was discovered in her serum. Sequencing analysis revealed that she has harbored a homozygous c.343A>T variant of the A4GALT gene.@*CONCLUSION@#The homozygous c.343A>T variant of the A4GALT gene probably underlay the p phenotype in this individual.

Study of the molecular characteristics of a Bweak phenotype due to a novel c.398T>C variant of the ABO gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular mechanism for an individual with Bweak subtype.@*METHODS@#Serological methods were used to identify the proband's phenotype. In vitro enzyme activity test was used to determine the activity of B-glycosyltransferase (GTB) in her serum. The genotype was determined by PCR amplification and direct sequencing of exons 5 to 7 and flanking sequences of the ABO gene. T-A cloning technology was used to isolate the haploids. The primary physical and chemical properties and secondary structure of the protein were analyzed with the ProtParam and PSIPRED software. Three software, including PolyPhen-2, SIFT, and PROVEAN, was used to analyze the effect of missense variant on the protein.@*RESULTS@#Serological results showed that the proband's phenotype was Bweak subtype with anti-B antibodies presented in her serum. In vitro enzyme activity assay showed that the GTB activity of the subject was significantly reduced. Analysis of the haploid sequence revealed a c.398T>C missense variant on the B allele, which resulted in a novel B allele. The 398T>C variant has caused a p.Phe133S substitution at position 133 of the GTB protein. Based on bioinformatic analysis, the amino acid substitution had no obvious effect on the primary and secondary structure of the protein, but the thermodynamic energy of the variant protein has increased to 6.07 kcal/mol, which can severely reduce the protein stability. Meanwhile, bioinformatic analysis also predicted that the missense variant was harmful to the protein function.@*CONCLUSION@#The weak expression of the Bweak subtype may be attributed to the novel allele of ABO*B.01-398C. Bioinformatic analysis is helpful for predicting the changes in protein structure and function.

Identification of a glycosyltransferase allele associated with Bw subtype and analysis of the protein structure / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular basis for an individual with Bw subtype.@*METHODS@#Routine serological reactions were used to determine the surface antigens of erythrocytes and antibodies in serum. PCR-sequence-based typing (PCR-SBT) was used to analyze the coding regions of the ABO gene and erythroid-specific regulatory element in its intron 1. Amplicons for exons 5 to 7 containing the variant site were subjected to TA cloning for the isolation of the haploid and verification of the sequence. The 3D structure of mutant protein was predicted with Pymol software. Changes of amino acid residues and structural stability were also analyzed.@*RESULTS@#Serological assay showed that the individual had weakened B antigen and anti-B antibody in his serum. His genotype was determined as ABO*B.01/ABO*O.01.01. Sequencing of the entire coding region of the ABO gene identified an additional heterozygous c.734C/T variant. No variant was found in the erythroid-specific regulatory element of intron 1. Haploid cloning and isolation has obtained an ABO*O.01.01 allele and a ABO*B.01 allele containing a c.734T variant, which has led to substitution of Thr by Ile at position 245 in the functional center of glycosyltransferase. Based on the 3D structure of the protein, the residues binding with the mutation were unchanged, but the bonding distance between the hydrogens was changed with the amino acid substitution. Meanwhile, the connections with water molecules were increased.@*CONCLUSION@#The c.734C>T variant of the GTB gene can lead to an amino acid substitution in the functional center of the enzyme, which in turn may affect the stability of glycosyltransferase B protein and reduceits enzymatic activity.

Molecular characterization of a recombination allele of ABO blood group / 中华医学遗传学杂志

OBJECTIVE@#To analyze the molecular characteristics of a recombinant allele of the ABO blood group.@*METHODS@#The ABO phenotype was determined with the tube method. The coding regions of the ABO and FUT1 genes were analyzed by PCR-sequence based typing. The ABO alleles of the proband were determined by allele-specific primer sequencing. The full sequences of the ABO gene of the proband and her mother were determined through next generation sequencing.@*RESULTS@#The red blood cells of the proband did not agglutinate with anti-H, and the sequence of the FUT1 gene was homozygous for c.551_552delAG.The proband was thereby assigned as para-Bombay. Bi-directional sequencing also found that she was heterozygous for c.261G/del,467C>T,c.526C>G,c.657C>T,c.703G>A,c.796C>A,c.803G>C and c.930G>A of the coding regions of the ABO gene. Allele-specific primer sequencing also found her to carry a ABO*A1.02 allele and a recombinant allele from ABO*O.01.01 and ABO*B.01. The recombination site was located between nucleotide c.375-269 and c.526, and the allele was maternally derived.@*CONCLUSION@#An recombinant allele of the ABO gene has been identified, which has originated from recombination of ABO*O.01.01 with the ABO*B.01 allele.

Study of the molecular basis for an individual with Bel variant due to deletion of B glycosyltransferase gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the molecular basis of an individual with Bel variant of the ABO blood group.</p><p><b>METHODS</b>The ABO antigen and serum antibody of the individual were detected by serological method. All coding regions and flanking introns of the ABO gene were amplified with PCR and sequenced bidirectionally. The haplotypes of the individual were analyzed by cloning and sequencing. A three dimensional model of the mutant protein was constructed and analyzed.</p><p><b>RESULTS</b>The individual has expressed a very weak B antigen on its red blood cells by absorption and elution testing, which was identified as a Bel variant phenotype. The heterozygous sites in exon 6 (261del/G) and exon 7 (297A/G, 484del/G, 526C/G, 657C/T, 703G/A, 796C/A, 803G/C, 930G/A) of the coding region of the ABO gene were identified by direct sequencing. Haplotype analysis showed that the individual has carried an O01 allele and a novel B allele. The sequence of the novel B allele was identical to B101 except for a del G at nucleotide position 484 (484delG), which was nominated as B120 by the Blood Group Antigen Gene Mutation Database (dbRBC NCBI). The 484delG mutation of the B allele has led to a reading frame shift and created a premature terminal codon for the glycosyltransferase (GT) enzyme. Prediction of the 3D structure suggested that the GT enzyme has become an incomplete protein only with its N-terminal region.</p><p><b>CONCLUSION</b>The 484delG mutation of the glycosyltransferase B gene has probably abolished or reduced the enzymatic activity and resulted in the Bel variant phenotype.</p>

Study of in vitro expression of human platelet ITGB3 gene nonsense mutation c.1476G>A / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the function of a novel nonsense mutation c.1476G>A of ITGB3 gene using an in vitro expression system.</p><p><b>METHODS</b>An eukaryotic expression vector containing ITGB3 c.1476G>A cDNA was generated by site-directed mutagenesis and transformed into E.coli. Plasmid DNA was extracted and sequenced to confirm the target mutations. Wild-type and mutant recombination plasmids were transfected into Chinese hamster ovarian cancer (CHO) cells by nonliposome method, and the stable expression cells were harvested by G418 screening. The ITGB3 gene mRNA transcription and GPIIIa expression level in CHO cells were detected with real-time quantitative PCR, Western blotting and flow cytometry, respectively.</p><p><b>RESULTS</b>The eukaryotic expression vectors of wild ITGB3 cDNA and c.1476G>A mutant were successfully constructed. CHO cells with stable expression were obtained after transfection and screening. Compared with the wild-type transfected cells, the amount of CD61 antigen expression was 37% and mRNA transcription level was only 6% in the mutant-transfected cells. Full length GPIIIa protein was found only in the stably wild-type-transfected cells, but not in mutant-transfected cells by Western blotting analysis.</p><p><b>CONCLUSION</b>The ITGB3 c.1476G>A mutation can decrease the transcription level and further affect GPIIIa synthesis and CD61 antigen expression.</p>

Molecular basis for an individual with rare p phenotype in P1Pk blood group system / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the molecular basis for an individual with rare p phenotype in the P1Pk blood group system.</p><p><b>METHODS</b>Erythrocyte blood group antigens and antibodies in serum were identified in the proband and five family members with a serological method. Coding regions and flanking untranslated regions of the α1,4-galactosyltransferase gene (A4GALT) encoding P1Pk antigens were amplified with polymerase chain reaction and directly sequenced. The haplotypes of A4GALT in the parents of the proband were also analyzed by cloning sequencing.</p><p><b>RESULTS</b>The proband was found with a rare p phenotype with anti-Tja antibody in his serum by serological method. The other family members all had a common P2 phenotype. The results of DNA sequencing showed that a cytosine was inserted at nucleotide position 1026 to 1029 (1026_1029insC) of both alleles of the A4GALT gene in the proband. The mutation has caused a reading frame shift and formed a mutant protein by extending 92 amino acid residues. The other family members were either heterozygous for the insertion or of the wild type at above position.</p><p><b>CONCLUSION</b>The 1026_1029insC mutation of the A4GALT gene is probably responsible for the p phenotype identified for the first time in Chinese population. The individual with the p phenotype possesses anti-Tja antibody.</p>

A rare Pk phenotype caused by a 433 C>T mutation of the β-1,3-N-acetylgalactosyltransferase gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the serological characteristics and molecular mechanism for a rare Pk phenotype of the P1Pk blood group system.</p><p><b>METHODS</b>The blood group of the proband was identified by serological techniques. The coding region and flanking intronic sequences of the β-1,3-N-acetylgalactosyltransferase gene (B3GALANT1) associated with the Pk phenotype were analyzed using polymerase chain reaction sequence-based typing.</p><p><b>RESULTS</b>The proband was identified as having a rare Pk phenotype including anti-P in her serum. The blood group of her daughter and husband showed a P2 phenotype. The nucleotide sequences of the B3GALANT1 gene of her husband and two randomly-chosen individuals were the same as the reference sequence (GenBank AB050855). Nucleotide position 433 C>T homozygous mutation in the B3GALANT1 was found in the proband, which has resulted in a stop codon at amino acid position 145, which may produce a premature protein capable of decreasing or inhibiting the activity of the β -1,3-N-acetylgalactosyltransferase. The nucleotide position 433 C/T heterozygous in the B3GALANT1 was found in her daughter.</p><p><b>CONCLUSION</b>The Pk phenotype resulted from 433 C>T mutation in the B3GALANT1 gene has been identified.</p>

Analysis of erythroid-specific blood group genes using un-mobilized peripheral stem cells cultured in vitro / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze specific expression of blood group genes using nucleated erythroid cells cultured from un-mobilized peripheral stem cells in vitro.</p><p><b>METHODS</b>Hematopoietic stem cells(HSC) bearing the CD34 antigen were isolated from peripheral blood by centrifugation and magnetic beads sorting, followed by suspension culture in vitro. Cells were collected from medium on various stages and analyzed by immunofluorescence. The RNA transcription of RH and ABO blood group genes was analyzed using culture cells on day 12.</p><p><b>RESULTS</b>A total of(3.19±0.13) ×10 (4) CD34+cells were isolated from about 50 mL peripheral blood with a recovery rate of 67.3%±2.7%. The cells amount in erythroid-lineage culture system on day 9 reached a plateau of a 237.1±15.5-fold amplification of the initial cell input. The stem cell-specific CD34 antigen was dropped off, while the erythroid-specific CD235a and CD240D antigens were increased in culture period. RHD/CE and ABO genes can be amplified using RNA extracted from culture cells on day 12, and genotypes of Rh and ABO systems by DNA sequencing were consistent with their serologic phenotypes.</p><p><b>CONCLUSION</b>A method was established to analyze the gene expression of erythroid blood group derived from un-mobilized peripheral stem cells cultured in vitro. It can be used to study the expression of various erythroid-specific genes.</p>

Effect of α -1,2 fucosyltransferase gene 682A> G and 547_552delAG mutations on the activity of fucosyltransferase / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the effect of α -1,2 fucosyltransferase (FUT1) gene 682A> G and 547_552delAG mutations on the expression of FUT1 mRNA and activity of α -1,2 fucosyltransferase.</p><p><b>METHODS</b>Recombinant expression vectors of FUT1 682A> G and FUT1 547_552delAG were constructed and transfected into COS-7 cells for stable expression screening. Expression of FUT1 mRNA was determined using real-time quantitative PCR. The activity of FUT1 was measured with high-performance liquid chromatography.</p><p><b>RESULTS</b>Stably transfected COS-7 cells with wild type FUT1, FUT1 682A> G and FUT1 547_552delAG were respectively obtained. The FUT1 mRNA level of transfected cells with 682A> G and 547_552delAG recombination vectors have measured 101.69% and 102.79% compared with that of wild type FUT1 transfected cells. A specific protein band with about 46 kD was confirmed in the 682A> G transfected cell lysates by SDS-PAGE electrophoresis and Western blotting with 6× His Tag antibody. Similar protein was not identified in the 547_552delAG cells lysates. Enzymes activity of FUT1 682A> G has measured 61.01% compared with wild type FUT1 protein, whilst the activity of FUT1 547_557delAG was completely abolished.</p><p><b>CONCLUSION</b>FUT1 682A> G and 547_552delAG mutations do not affect the transcript efficiency, although various mutations have different impact on the enzyme's activity.</p>

A rare p phenotype caused by a 26-bp deletion in α 1,4-galactosyltransferase gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To delineate serological features and genetic basis for a rare p phenotype of P1Pk blood group system found in a Chinese individual.</p><p><b>METHODS</b>Serological assaying was carried out for a proband with unexpected antibody found in his serum using specific antibodies and panel cells. Coding regions and flanking introns of α 1,4-galactosyltransferase gene (A4GALT) associated with the p phenotype were screened with polymerase chain reaction and DNA sequencing.</p><p><b>RESULTS</b>A rare p phenotype of the P1Pk blood group system has been identified with red blood cells from the proband, whose serum contained anti-Tja antibody which can agglutinate and hemolyze with other common red blood cells. Other members of the proband's family were all normal with P1 or P2 phenotype. DNA sequencing has identified in the proband a homozygous 26 bp deletion at position 972 to 997 of the A4GALT gene. The deletion has caused a shift of the reading frame, resulting in a variant polypeptide chain with additional 83 amino acid residues compared with the wild-type protein. Other family members were either heterozygous for above deletion or non-deleted.</p><p><b>CONCLUSION</b>A 26 bp deletion at position 972 to 997 of the A4GALT gene has been identified in a Chinese individual with p phenotype.</p>

Molecular basis of the B(A)phenotype and its pedigree analysis / 中华检验医学杂志

Objective To investigate the serological characteristics and molecular basis of the B (A)phenotype in ABO blood group and provide the data for clinical transfusion of individuals with B(A) phenotype.Methods The ABO group antigens on red cells of the proband,family members and donors were identified by monoclonal antibodies and the ABO antibodies in sera were detected by the standard A,B,O cells.The compatibility testing for the proband and donors was detected by salted test,polybrene test and antiglobulin test.The coding region of exon 6 to exon 7 in ABO gene was amplified by polymerase chain reaction(PCR) and the PCR products were sequenced.The haplotypes of proband were analyzed by cloning and sequencing.Results It was showed that both A and B antigens were detected on red cells of the proband and her two family members,and there was anti-A_1 antibody in their sera.The serological phenotype of the samples are identified as the A_2B.DNA sequencing showed 261 G/del,297A/G,526C/G,657C/T,700C/G,703G/A,796C/A,803G/C,930G/A heterozygotes in exon 6 to exon 7.It can be deduced that genotype in the proband is B(A)_(02)/O_(01).The genotypes of her mother and grandmother-in-law were B(A)_(02)/B_(101) and B(A)_(02)/O_(01),respectively.After cloning and sequencing,two alleles B(A)_(02) and O_(01) in proband was showed.B(A)_(02) has snigle nucleotide change(700 C>G),which resets replacement of proline with alanine at position 234.Two donors with phenotype A_2B were identified as genotype B(A)_(02)/O_(01) and A_(208)/B_(101),respectively.The results of crossmatch testing is in accordane between the proband and two donors and there was no clinical adverse reaction after transfusion.Conclusions 700C>G in α-1,3galactosyltransferase allele(B allde)can result in B(A)phenotype in individuals with the phenotype of A_2B.The donors in the transfusion for the individuals with B(A) phenotype should include individuals with A_2B phenotype.

Establishment and application of hnman platelet antigen genotyping with PCR sequencing-basod typing method / 中华检验医学杂志

Objective To establish a PCR sequencing-based typing (PCR-SBT) method for simultaneous genotyping of human platelet antigen HPA-1 to HPA-16w.Methods All DNA polymorphism sites of HPA-1 to HPA-16w were obtained from the immuno polymorphism database.The specific primers were designed using Primer Premier 5.0 software to amplify nucleotide acid fragments encompassing each HPA polymorphism site.The primer sequence and PCR condition were optimized to obtain specific and single amplification product.The PCR product was purified and then sequenced to determine the HPA genotypes.Two standard DNA samples were detected using the HPA PCR-SBT method to examine the accuracy d this method.Sixteen reference samples (including 6 interference samples with HPA gene mutations) provided by 14th platelet immunology workshop of international society of blood transfusion (ISBT) in 2008 were also tested by this home-brew HPA PCR-SBT method.Results Total eleven pairs of primers were designed to amplify and sequence the sixteen HPA systems.The HPA genotypes of two standard samples were 1aa/2aa/3ab/4aa/5ab/6aa/7aa/8aa/9aa/10aa/11aa/12aa/13aa/14aa/15aa/16aa and 1aa/ 2aa/3aa/4aa/5aa/6aa/7aa/8aa/9aa/10aa/11aa/12aa/13aa/14aa/15aa/16aa,respectively.The 256 HPA genotypes of 16 reference samples were clear.128 genotypes among them were completely accordance with the results provided by ISBT report.Conclusions The PCR-SBT assay combining high-throughput DNA sequencer established in the study provides a simple,rapid and accurate method for HPA-1 to HPA-16w systems genotyping.The assay is suitable for routine clinical HPA genotyping and shows a broad prospect in further applications.

The molecular genetics basis for ABw07 phenotype of ABO subtype / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the molecular genetic basis for a case of ABw07 phenotype of ABO subtype.</p><p><b>METHODS</b>The ABO group antigens on red blood cells of the proband were identified by monoclonal antibodies and the ABO antibody in serum was detected by the standard A, B and O cells. The exons 6 and 7 of the ABO gene was amplified by PCR and the PCR product was sequenced directly after enzyme digestion. The amplified product was also cloned by TOPO TA cloning sequencing kit to split the two alleles apart, chosen colonies were sequenced bidirectionally. The samples of the parents and one sister of the proband were collected, then the blood group serological test and sequence analysis for exon 6 to 7 of ABO gene were performed.</p><p><b>RESULTS</b>Both A and B antigen were detected on red blood cells of the proband and there was anti-B antibody in the serum. There was no 261G deletion. And the 297A/G, 467C/T, 526C/G, 657C/T, 703G/A, 796C/A, 803G/C, 930G/A, 1055G/A and 1096A/G loci were heterozygotes by direct DNA sequencing, which can be assigned for A102Bw07 genotype. After cloning and sequencing, two alleles of A102 and Bw07 were obtained. The Bw07 has one nucleotide change of G to A at nucleotide 1055 compared with B101, which results in an amino acid change from Arg to Gln at nucleotide 352. The Bw07 in the proband was inherited from his mother, and the serological characteristic of the ABO blood group and the sequence of exons 6 and 7 of the mother were the same as that of the proband.</p><p><b>CONCLUSION</b>The G to A at nucleotide 1055 of alpha -1, 3 galactosyltransferase gene (B gene) can result in BW7 phenotype, with anti-B antibody in serum.</p>

C721T mutation of the alpha 1,3 galactosyltransferase gene responsible for Bw subgroup / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To gain an insight into the molecular genetic basis of Bw subgroup of ABO blood group system.</p><p><b>METHODS</b>Three Bw phenotypes were confirmed by standard serological techniques. The enhancer, promoter and exons 1-7 including flanking introns of ABO gene were amplified and directly sequenced after PCR amplified fragments being purified by gel. Exons 6 and 7 were also sequenced after pcDNA3.1 (-) vector transformation. The sequence specific primer-polymerase chain reaction was performed to confirm the mutations detected by sequencing in this study.</p><p><b>RESULTS</b>Genotypes of three individuals were Bw/O by direct sequencing, there were G deletion heterozygous at position 261 and C/T heterozygous at position 721. A normal O allele was confirmed by cloning sequencing and 721 C>T mutation of the alpha 1, 3 galactosyltransferase (B allele) gene was also observed, which caused amino acid 241 Arg>Trp substitution. This mutation was not detected in 140 random samples by PCR-SSP.</p><p><b>CONCLUSION</b>The mutation of 721C>T in the alpha 1, 3 galactosyltransferase gene may be one of the molecular genetic bases of Bw phenotype.</p>

Detection of fetal RhCcEe genotype in maternal plasma / 中华检验医学杂志

Objective To detect fetal RhCcEe genotype from fetal DNA in maternal plasma for noninvasive prenatal diagnosis.Methods DNA from maternal plasma sample was extracted by use of QIAamp DNA Kit. The existence of fetal DNA was confirmed by amplified fetal SRY gene. The fetal RhCcEe gene was amplified by polymerase chain reaction (PCR) from 30 pregnant maternal plasma. The results of fetal RhCcEe genotype were evaluated retrospectively by the serologic analysis of infant and pregnant woman RhCcEe phenotype.Results Among the 30 samples, 13 were the same phenotypes between mother and infant, 17 were different. When mother phenotypes were RhCC, cc, EE and ee homozygous, the deleted allele gene can be successfully amplified from mother plasma.Conclusion Noninvasive fetal RhCcEe genotyping is reliable. When the mother was homogyzous, genotyping the fetal CcEe alleles was very significant and useful for HDN (hemolysis disease of newborn) diagnosis and therapy.

Identification of the para-Bombay phenotype AB h m / 中国输血杂志

Objective To identify para-Bombay phenotype AB h m. Method ABO and H phenotype were typed. Absorption and elution were performed. Saliva was tested by inhibitory reaction. Direct sequencing was performed and family study was done. Results Proband was typed as rare para-Bombay phenotype AB h mand anti-H was detected in his serum. Family study suggested that the inheritance was autosomal recessive. Conclusion Rare AB h m phenotype was identified and anti-H has been detected in his serum.

Identification the rare p phenotype in serological and molecular biological methods / 中国输血杂志

Objective To identify the p phenotype. Method P blood group system was identified using p phenotype cells,anti PP 1 P k antiserum,and direct DNA sequencing.Result and Conclusion Proband was typed as p, with rare anti PP 1 P k in the serum,family study suggested that inheritance was autosomal recessive.

Research on molecular genetic basis for Jk(a-b-) phenotype / 中国输血杂志

Objective To investigate the molecular basis for Jk(a b ) phenotype.Methods Routine serologic testing for phenotype.Genomic DNA covering 4～11 exons and partial introns of JK gene was amplified by ploymerase chain reaction.The PCR products were excised and purified from agarose gels with a kit,then fragments were directly sequenced.Results G mutated to A in the 3'acceptor splice site of intron 5;A to G at 78 site from the 3'end of intron 3;C to T at 84 site from the 5'end of intron 8; A to G at 588 site of exons ( exon 7); G to A at 838 site of exons (exon 9).The splice site mutation (G→A) of intron 5 may cause the skipping of exon 6.Conclusion G to A mutation in the 3'acceptor splice site of intron 5 maybe one of the molecular basis for Jk(a-b-) phenotype

Molecular genetic analysis of Ael subgroup of the ABO blood group system / 中国输血杂志

Objective To understand the molecular genetic basis of Ael subgroup of ABO blood group system in the Han nationality.Method 2 Ael individuals were defined by standard blood group serological techniques,and genomic DNA was prepared for PCR SSP genotyping.Primers were designed and synthesized to amplify complete exon 6 and 7 including flanking intron sequence,and direct sequencing of gel purified PCR amplified fragments was performed using Bigdye Sequencing kit.Result A possibility of regarding the Ael allele as A2,B,O1 and O2 genes had been eliminated by the PCR SSP assay.According to the sequence analysis,Ael gene had 2 mutations of which one was a nucleotide substitution at position 532 in intron 5 (C to T),and the other was a single nucleotide(G) insertion at position 798 to 804 in exon 7 which alter the 86 amino acids sequence of the glycosyltransferase and furthermore extend the translated proteins by 37 amino acids compared with A1 allele.Conclusion The mutations of (789 804)G insertion and C(I 5/532)T substitution is the molecular genetic basis for Ael phenotype.