Bombay Phenotype

 Bombay Phenotype is a rare genetic trait that originally started in Bombay , are hh individuals that failed to produce substance H (antigen H) which is needed for the adhesion of antigens A and B sugars on the surface of red blood cells. Individuals with Bombay Phenotype can be any blood type "A", "B" , "AB" or "O", however due to the lack of antigen H, their blood type is expressed as "O" when a quick blood test is run.