Blood Diathesis in a Patient of Rare Blood Group 'Bombay Phenotype'.

Bombay blood group or Oh phenotype is a rare autosomal recessive phenotype within the ABO blood grouping system. It occurs due to a mutation in the H gene that produces H antigen on red blood cells (RBCs). Individuals with two mutant H genes lack H antigen on RBCs and have anti-H antibodies in serum. At the time of blood grouping, this blood group mimics O blood group but it shows incompatibility with O group blood during cross matching. Several studies have reported an association of decreased von Willebrand factor (VWF) levels in plasma with ABO blood groups. Here we report a case of a 19-year-old male, who was labelled as Bombay phenotype and later found to have markedly reduced plasma VWF levels.