Neonatal testing leading to the identification of B_h (para-Bombay) phenotype in the mother: case report with review of the literature

Abstract Para-Bombay is a rare phenotype with homozygous nonfunctional FUT1 gene and normal FUT2 leading to H-deficient red blood cells (RBCs) or without ABH substances, depending on inheritance of the ABO gene. This case about 5-day-old male baby suffering from sepsis who required 45-mL packed RBC transfusion. The baby’s sample tested as A 1 B, D+ mother’s group O, 4 discrepancy due isoagglutinins. Further workup anti-H lectin was negative, which suggested mother be O h , D+. Antibody screening panreactive negative autocontrol, suggestive anti-H. titer immunoglobulin (Ig)M 64, IgG using dithiothreitol 8, anti-IH absent. adsorption elution test that RBCs were devoid B antigens. father’s clearly D+; hence, cis- AB ruled out in baby. secretor study saliva revealed presence H substances neutralized polyclonal antisera. Therefore, we concluded para-Bombay (B ) phenotype. highlights importance reverse grouping resolving discrepancies between child―in this because an incongruous type previously