Rare and Unique: Understanding the Bombay Blood Group
The Bombay blood group, also known as the h/h blood group, is an extremely rare blood type. It was first discovered in Mumbai (then called Bombay), India.
The story of the Bombay blood group begins in 1952 in Mumbai, India. A patient required a blood transfusion but exhibited an adverse reaction to the ‘universal’ O-type donor’s blood. This unexpected response puzzled doctors and led to further investigation. Dr. Y.M. Bhende and his colleagues conducted extensive research and discovered this new blood group named the ‘Bombay phenotype.’
Prevalence
In global terms, the Bombay blood group is infrequent. Although its prevalence among Indians living in Mumbai is slightly higher than elsewhere in the world, it remains remarkably unusual, with only about 4 per million individuals in the local population possessing this phenotype.
Characteristics
The uniqueness of the Bombay blood group lies in its lack of antigens A, B, and H on red cells—antigens that are common to people within the ABO system. As a result, individuals with this blood type can donate to any member of the ABO system but can only receive from other Bombay phenotype individuals.
Genetic Basis
The genetic basis for possessing such an exceptionally rare phenotype involves inheriting recessive genes from both parents. A person will have this type only if their parents pass on the recessive gene responsible for this attribute.
Medical Implications
The rarity of the Bombay phenotype can cause significant challenges during medical treatment, particularly when frequent transfusions are needed, such as during surgeries or for patients with Thalassemia. The primary concern is that most hospitals initially check for compatibility within the ABO system only, potentially overlooking individuals with an h/h classification. This oversight may lead to robust hemolytic reactions if incompatible blood is transfused.
Awareness and Precautions
Over time, increased awareness about this scarce blood type has necessitated additional steps during diagnosis or transfusion processes to ensure no adverse reactions occur due to mismatches between h/h and standard types A, B, O, or AB. These extra precautions help safeguard patients with the Bombay phenotype during medical treatments requiring blood transfusions.
By understanding these details about its discovery, characteristics, genetic basis, medical implications, and necessary precautions, we understand why the Bombay blood group remains a fascinating subject within hematology and genetics.