Phenotype prediction by DNA-based typing of clinically significant blood group systems in Jordanian blood donors

HAPTOGLOBIN POLYMORPHISM AND CHRONIC TENDINOPATHY

Introduction: Tendinopathy is a pathology of tendons of multifactorial origin displayed clinically as chronic degenerative tissue resulting in dysfunction and painful musculoskeletal system. Genetic implications in tendinopathy are not fully elucidated. Haptoglobin (Hp) polymorphism has been investigated for potential role in several diseases such as cardiovascular diseases. This study aims at investigating Hp polymorphism potential association with chronic tendinopathy in Jordan. Materials and Methods: A hospital-based case-control study, of 101 patients diagnosed with chronic tendinopathy and 104 age and gender matched controls, was employed and Hpphenotypes distributions were determined using Sodium Dodecyl Sulphate Polyacrylamide gel electrophoresis technique. Results: showed a significant association between tendinopathy cases and controls in relation to Hpphenotypes frequencies (Fisher’s Exact Test, [Formula: see text]). Odd ratios showed that the odds of tendinopathy cases in Hp2.1 group were reduced while odds in Hp2.2 and Hp1.1 were increased by 3.22 and 7.34 times, respectively, as likely compared to the controls. Conclusion: Results suggested that Hppolymorphism might play a role in chronic tendinopathy genesis.

Heterogeneity of O blood group in India: Peeping through the window of molecular biology

BACKGROUND:

Molecular genotyping of ABO blood group system has identified more than 60 “O” group alleles based on the single-nucleotide polymorphisms present in the ABO gene. Heterogeneity of O group alleles has been observed in various countries from South America, Europe, Middle East, and Asia. India is a vast country with more than 1300 million population which is divided into various ethnic and tribal groups. However, very little is known about the heterogeneity of O alleles in Indians.

MATERIALS AND METHODS:

A total of 116 O group individuals from the mixed population of Mumbai, India, were enrolled in the present study. DNA was extracted using the standard phenol–chloroform method. The exons 6 and 7 of the ABO gene were genotyped by polymerase chain reaction-single-strand conformation polymorphism and/or DNA sequencing. The genotyping results were compared with our earlier findings.

RESULTS AND DISCUSSION:

Overall, ten different genotypes were identified. Three rare alleles, namely, O05, O11, and O26 were seen in the mixed group category. These results suggest that there is an internal heterogeneity in the mixed group while Dhodias and Parsis, the groups which were screened earlier, seem to be more homogenous groups. An important piece of information emerges out from this study, that is, O01O02 genotype is expressing some selective force in population groups screened in India as well as many other groups worldwide.

CONCLUSION:

In the future, molecular genotyping of the ABO blood group system among different ethnic and tribal Indian groups would help in generating data to fill up the gaps in the molecular ABO map of the world.

Allelic Prevalence of ABO Blood Group Genes in Iranian Azari Population

INTRODUCTION

ABO blood group system is the most important blood group in transfusion and has been widely used in population studies. Several molecular techniques for ABO allele's detection are widely used for distinguishing various alleles of glycosyl transferase locus on chromosome 9.

METHODS

744 randomly selected samples from Azari donors of East Azerbaijan province (Iran) were examined using well-adjusted multiplex allele- specific PCR ABO genotyping technique.

RESULTS

The results were consistent for all individuals. The ABO blood group genotype of 744 healthy Azari blood donors was: 25.8% AA/AO (2), 7.6% AO (1), 1.6% BB, 11.3% B0 (1), 10% AB, 9.3% 0(1)0(1) and 15.3%0(1)0(2). The highest genotype frequency belonged to O01/O02 genotype (15.3%) and the lowest frequency belonged to A101/A102 genotype (0.4%).

CONCLUSIONS

The frequencies of ABO alleles didn't show significant differences between East Azerbaijan province population and that of other areas of the country. Meanwhile, statistical analysis of frequencies of A and B alleles between East Azerbaijan province population and neighbor countries showed significant differences whereas the frequency of allele O between them did not show significant difference (P>0.05).

CONCLUSIONS

The frequencies of ABO alleles didn't show significant differences between East Azerbaijan province population and that of other areas of the country. Meanwhile, statistical analysis of frequencies of A and B alleles between East Azerbaijan province population and neighbor countries showed significant differences whereas the frequency of allele O between them did not show significant difference (P>0.05).

KEL*02 alleles with alterations in and around exon 8 in individuals with apparent KEL:1,-2 phenotypes

BACKGROUND AND OBJECTIVES

Antibodies to antigens in the Kell blood group system, especially anti-KEL1, are involved in both haemolytic disease of the newborn and foetus and haemolytic transfusion reactions. Correct typing results are important and discrepancies between serologic and genetic typing must be resolved. Here, we describe the investigation of three healthy individuals who were initially phenotyped as KEL:1,-2.

MATERIALS AND METHODS

Antigen typing was performed by standard serological techniques and by flow cytometric analysis. The KEL*01/02 polymorphism was tested by an allele-discrimination TaqMan assay as well as by PCR with allele-specific primers and PCR-RFLP. DNA sequencing of the KEL coding region was also performed.

RESULTS

Two KEL*02N alleles with mutated splice sites around exon 8 were identified: intron 7 -1g>c (novel) and intron 8 +1g>t (previously reported in one case of K(0)). In the third sample, a missense mutation in exon 8, 787G>A (novel) predicting Gly263Arg, was detected on a KEL*02 allele and associated with dramatically weakened KEL2 antigen expression.

CONCLUSION

Resolution of discrepant phenotype/genotype results identified silencing mutations in or around exon 8. A combination of molecular and serologic methods has the potential to improve the quality of test results and was required to ensure both the accurate KEL2 antigen status and KEL*01 zygosity of these individuals.

Molecular genotyping and frequencies of A1, A2, B, O1 and O2 alleles of the ABO blood group system in a Kuwaiti population

Expression of the highly polymorphic ABO gene cluster is commonly investigated for blood transfusion and analysis, but little information is available for Middle Eastern populations. This study determined the major ABO allele frequency in a Kuwaiti Arab cohort using a multiplex PCR-RFLP technique; 355 unrelated blood donors of phenotype A1 (46), A2 (31), A1B (6), A2B (4), B (97) and O (171) were genotyped. DNA fragments of 252 (251 for O1) and 843 (842 for A2) bp spanning the two major exons, 6 and 7, of the ABO gene were amplified and digested with HpaII and KpnI. Thirteen different genotypes could be identified when combining the A1, A2, B, O1 and O2 alleles from the digestion patterns: 1 A1 A1 (0.28%), 6 A1 A2 (1.69%), 38 A1 O1 (10.71%), 1 A1 O2 (0.28%), 1 A2 A2 (0.28%), 30 A2 O1 (8.45%), 6 A1 B (1.69%), 4 A2 B (1.13%), 12 BB (3.38%), 79 BO1 (22.25%), 6 BO2 (1.69%), 167 O1 O1 (47.04%) and 4 O1 O2 (1.13%). Two of the combinations (A2 O2, O2 O2) were not found. All genotypes determined were consistent with the serotypes. The frequencies of the five alleles in the Kuwaiti sample population were ABO*A1 = 0.0746, ABO*A2 = 0.0592, ABO*B = 0.1676, ABO*O1 = 0.6831 and ABO*O2 = 0.0155. These results are discussed with reference to gene frequencies reported for other ethnic groups.

ABO blood group in Kuwaitis: detailed allele frequency distribution and identification of novel alleles

BACKGROUND

The ABO blood group is clinically the most important blood group system and can now be genotyped easily by DNA-based methods without family studies.

STUDY DESIGN AND METHODS

Samples (n = 166) from a Kuwaiti population were phenotyped by standard serologic techniques for the ABO blood group and genotyped for the ABO locus by an established multiplex polymerase chain reaction protocol followed by single-strand conformation polymorphism (SSCP) analysis. Nonstandard SSCP patterns were investigated by DNA sequencing of exons 6 and 7 and, if necessary intron 6.

RESULTS

Standard SSCP patterns identified six classical alleles in this population: A101 (0.1115), A102 (0.0181), A201 (0.0301), B101 (0.1627), O101 (0.3103), and O201 (0.2500). One A, 1 B, and 8 O variant alleles were identified (total frequency, 0.1175). All variant alleles were each present in one or two chromosomes (< or =0.0060) in our samples except O109 (0.0813). Three of these 10 variant alleles were novel alleles defined by newly identified single-nucleotide polymorphisms in exon 7 (527G>A, 687C>T, and 1116G>A). One new base substitution result in amino acid change.

CONCLUSIONS

This is the first study reporting the detailed distribution of ABO alleles and genotypes in Kuwaitis. Sixteen alleles were identified, including 3 novel alleles.

Genetic basis of the K0phenotype in the Swedish population

BACKGROUND

The absence of all Kell blood group antigens (K(0) phenotype) is very rare. K(0) persons, however, can produce clinically significant anti-Ku (K5) after transfusion and/or pregnancy and require K(0) blood for transfusion. Ten alleles giving rise to the K(0) phenotype have been reported: different populations were studied although none from Scandinavia.

STUDY DESIGN AND METHODS

Three K(0) samples were identified by blood banks in Sweden (Uppsala, Umeå, and Linköping) during a 20-year period. Kell antigen typing was performed with standard serologic techniques by the respective blood banks and K(0) status was confirmed by the International Blood Group Reference Laboratory in Bristol, England. Polymerase chain reaction and DNA sequencing of the KEL coding region (exons 1-19) was performed on genomic DNA.

RESULTS

The Uppsala K(0) was homozygous for a 1540C>T substitution in exon 13, leading to an immediate stop codon. The Umeå K(0) was homozygous for 1023delG in exon 8 that results in a frameshift and a premature stop codon in exon 9. In the Linköping K(0), a previously reported mutation g>a at +1 of intron 3 was found.

CONCLUSION

Two novel and one previously reported null alleles at the KEL locus are described. The identified nonsense mutations abolish expression of the Kell glycoprotein and are thus responsible for the K(0) phenotype in these Swedish families.