The blood specimen of a 30-year-old male donor showing a discrepancy in cell and serum grouping was targeted for detailed study at the blood bank at tertiary care hospital in South Gujarat. Forward grouping showed group as “O” RhD positive and reverse grouping as group “A.” Further testing confirmed that the individual's blood group was para-Bombay A (para-AH). Family members were screened, and younger brother was also identified as para-Bombay phenotype. The para-Bombay phenotype is very rare, and only a few cases have been reported from India. This blood group is characterized by the absence of ABH antigens on red blood cells (RBC's) with the presence of ABH substances in body secretions or by the weak expression of ABH antigens on RBC's with the absence or presence of substances in body secretions. This rare phenotype can be mislabeled as “O” if all detailed investigations are not performed.

Background and Objectives The Bombay phenotype cases do not express the ABH antigens on red blood cells and in body secretions because of the inactivation of H (FUT1) gene and Secretor (FUT2) genes. This rare phenotype was first detected in Mumbai, India, previously known as ‘Bombay’. The presence of T725G mutation in FUT1 gene and deletion of FUT2 gene, both in homozygous condition, has been found to be the cause of Bombay phenotype in individuals originating from India. Thus, the objective of this study was micromapping of all the cases of Bombay phenotype identified at our Institute during the last 60 years and molecular analysis of FUT1 and FUT2 genes in a large number of Bombay phenotype cases. Material and Methods Bombay phenotype cases were confirmed by conventional serological techniques. FUT1 gene in 89 cases was screened for T725G alteration by PCR–RFLP. Deletions in FUT2 gene were detected by specific pairs of primers. Similarly, FUT1 and FUT2 genes were sequenced in all control samples. Results In the present series, 74·2% Bombay phenotype cases were originating from Maharashtra state. T725G was found to be the only mutation in homozygous condition in FUT1 gene in all cases of Bombay phenotype. Similarly, they were homozygous for 10‐kb deletion covering entire FUT2 gene. Conclusion All the cases of Bombay phenotype reported in this study, originating from different states of India, showed only T725G alteration in FUT1 gene and 10‐kb deletion covering entire FUT2 gene suggesting the unicentric origin of this rare phenotype in India.

Objectives This study evaluated the red blood cell (RBC) Lewis phenotypes by simple haemagglutination technique and molecular genotyping in healthy individuals. Background The expression of Lewis antigen on RBCs is dependent on the interaction of FUT3 and FUT2 genes. Complexity of the genetic control of Lewis antigen expression and the error‐prone nature of Lewis phenotyping result in non‐genuine RBC Lewis phenotypes, which could be misleading. Materials and Methods ABO blood group and RBC Lewis phenotypes were determined by conventional haemagglutination tube techniques. FUT2 and FUT3 genotypes were analysed by polymerase chain reaction and direct DNA sequencing. The RBC Lewis phenotypes were also inferred from the FUT2 and FUT3 genotyping results. Results The frequencies of RBC Lewis phenotypes typed by the conventional tube test were Le(a+b−) 19.63%, Le(a−b+) 49.32% and Le(a−b−) 31.05%, whereas the frequencies inferred from the FUT2 and FUT3 genotypes were Le(a+b−) 20.09%, Le(a−b+), 59.82%; Le(a−b−), 17.81%; and Le(a+b+), 5 (2.28%). The Le(a+b+) phenotype was not detected by the tube test, and a significant difference was observed in the frequencies of the determined Le(a−b−) and Le(a−b+) phenotypes. Conclusion The phenotyping and genotyping of Lewis blood group system reveal a high rate of discordance in the frequencies of Lewis phenotypes among the healthy individuals.