- The Bombay blood group is an extremely rare blood type where red blood cells lack the H, A, and B antigens and plasma contains antibodies against these antigens. - It was first discovered in Bombay, India in 1952 in about 1 in 10,000 people in Mumbai. Worldwide prevalence is about 1 in 1 million. - People with this blood group can only receive blood from other Bombay blood group donors, as their blood will hemolyze if receiving blood from other blood groups. - It is important for those with the Bombay blood group to register with blood banks so their rare blood can be available in emergencies.

1. BOMBAY BLOOD GROUP

2. H SystemOn group ‘O’red cells there is no Ao rBantigen&the membrane expresses ‘H’antigen H is a precursor ofA&B antigens.A&Bpersons have less H substance thanO group BOMBAY PHENOTYPESeen in persons with red cells which lackH,A&B antigens&whose plasma contains antiH,antiA&antiB

3. First discovered in Bombay by Dr.Y.M.Bhende

4. Present in about 4 per million of human population generaly

5. In Mumbai it is 1 in 10,000

6. More common in India

7. 179 cases reported in India

8. 35to 40 in Mumbai

9. 12 in West bengalWhen Bombay blood group was first encountered it was found not to contain AorB antigen so was thought to be ‘o’ blood group

10. But these pts could not safely receive normal ‘O’blood group,this proved to be because they lack ‘H’antigenGENOTYPEArises from inheritance of ‘hh’at H locusThis genotype do not produce ‘H’carbohydrate which is the precursor for A&B antigensBoth parents must carry recessive allele to transmit this blood type to children Pts with this blood group should be transfused only with this group because hemolysis occurs if transfused with other groups which may lead to death