What is the Bombay Blood Group and How was it Discovered?
Knowing one’s blood group is very important for several reasons. It saves time when a person requires blood during an emergency. People are also able to donate blood to a loved one if they know their blood group. Donating blood is a virtuous act as it helps to save the lives of many people. When a person donates blood, the doctors examine the blood to ensure that the person is fit to donate blood. They also check whether the blood group of the person donating the blood is compatible with the blood group of the person for whom the blood is required. It is mandatory to match the blood group before donating blood, as it can be dangerous to give the wrong blood group type to a patient.
It is popularly believed that the blood group O negative is the rarest blood group since it is found only in a few people. Not many people are aware that the rarest blood group is not O negative but a blood group found only in one person out of millions, called the Bombay Blood Group. This blood group is also called the rare of the rarest blood group.
Let’s learn more about this rarest blood group, the Bombay Blood Group, and answer questions like what it is, how it is formed in the body, where it is found, and why it is known as the Bombay blood group.
Bombay Blood Group: Occurrence and Structure
Bombay Blood Group is the rarest blood group that is found only in 0.0004 percent of the world population. This means that only one person in 10,000 people in India has this blood type. This blood group is also called HH blood type or Rare ABO blood group. This blood group was first discovered in 1952 by Doctor YM Bhende.
This blood group is called Bombay Blood because it was first found in a few people of Bombay. Bombay blood group or the Hh blood group has an antigen, called the H antigen, which is found almost on all RBCs. It is the building block for the production of the antigens for the ABO blood group. The red blood cells (RBC) of the Bombay blood group have ABH antigens, and their sera contain anti-A, anti-B, and anti-H. Although anti-H has not been discovered in the ABO group, it has been found in the Pre transfusion Test. This H antigen acts as a building block in the ABO blood group. The absence of H antigen is termed the Bombay phenotype.
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Where Bombay Blood is Found?
Bombay blood type is mostly found in people with a close blood relation to people having this blood type. The percentage of people who hold this phenotype in Bombay is only 0.01 percent. If the parent has the Bombay blood type, then there is a strong chance that the blood type of one or more children will also be Hh. According to estimates, only 4 per million people in the world have this blood type. The percentage of people with Bombay blood group is higher in Mumbai, where 1 in every 10,000 people have this blood type. Bombay was also the place where this blood group was first discovered.
The percentage of people having this blood type is higher in South Asia because of close community marriages that lead to inbreeding. In India, almost one in 7,600 to 10,000 are born with the Bombay Blood Group.
Blood Group Types
Blood groups can be classified into 4 types - A, B, AB, and O. This classification was derived in the year 1900-1902, by K. Landsteiner, who divided the human blood into these four groups. Except for the blood group type O, the other three blood groups A, B, AB groups have corresponding antigens. This is why people with blood group O can give blood to any blood group and are called the universal donors. The blood group AB is called the Universal Recipient as people with this blood type can take blood from all blood groups: A, B, AB, and O.
Transfusion Limitations of the hh Blood Type
People with the hh blood group can only be given transfusions of autologous blood (blood from another person with the same Bombay hh phenotype type) which is a very rare occurrence. In case such a person is given transfusions of A, B, AB, or O, blood group, the body may reject the blood, leading to serious complications. People with the hh blood group can donate their blood to people with ABO blood types.
In India, there is an unofficial registry for the Bombay blood group, and this list has over 350 donors registered from across India. But at any given time, only 30 active donors are available. Also, the blood banks do not generally store the ‘hh’ group like all the other blood groups. It is because this blood type is extremely rare and has a short shelf-life of between 35 to 42 days.
What is Golden Blood?
Although Bombay blood group or hh blood is a rare blood type, scientists have discovered a blood type that is even rarer than the Bombay blood group. Less than 50 people in the world are known to have this blood type, making it the rarest of all blood types in the world. This blood group is known as the golden blood type or Rh null blood group. It has no Rh antigens (proteins) on the red blood cell (RBC). This blood type was first seen in Aboriginal Australians. People with this blood type find it extremely difficult to get blood donations since this blood is incredibly scarce. A person with Rh null person blood type has to rely on the small network of donors with regular Rh null around the world in case of blood donation requirements. There are only nine active donors for Rh null blood in the world, making it the world’s most precious blood type. This is why this blood type is popularly known as the golden blood.
Interesting Facts about Bombay Blood Group
People with the Bombay blood groups lack the other expressions of the A, B, or O genes inherited from parents.
The Bombay Phenotype Red Cells do not have the AB, H Ags.
They do not react with anti- A, anti -B, and anti-A, B, and anti H
Bombay Serum has anti-A, -B, and anti-H.
Bombay blood is not compatible with all ABO donors because the HAg is present in all ABO blood groups
Only the blood from another individual with the Bombay blood group can be transfused to a person with this blood group.
FAQs on Bombay Blood Group
1. What is the Bombay blood group and how it is discovered? Also, where Bombay blood is found?
Bombay Blood Group is the rarest blood group that was discovered in 1952 when an injured railway worker and a stabbing victim required a blood transfusion in Mumbai, which was known as Bombay at that time. None of the known blood types worked for them at that time. When their blood samples were mixed with any of the other regular blood types, the blood coagulated or clumped up.
The group of three doctors treating these patients at the Seth Gordhandas Sunderdas Medical College in the city tried to match their blood with over 160 donors but failed to get a match. After a long and tiresome search, they found a resident in the city whose blood type matched the blood group of both patients.
It was concluded that this blood group was not the regular and known blood type found in most people. This never before identified blood group was then named Bombay Blood Type or the HH Blood Type after one of India’s most famous cities and the city Bombay where this blood type was discovered.
2. Is Bombay Blood Group often mistaken as blood group O?
Bombay Blood Group does not have A or B antigens, and this is why it is often mistaken as O blood. This blood type can only be determined when a specific test for H antigen is done. This test is often unavailable in India, and it is the only test that can differentiate between O and Bombay Blood groups. Incorrect diagnosis of this blood type can lead to several complications, including death.
3. How is the testing done for the Bombay blood group?
This blood group type requires an antigen H blood test to check the blood for this antigen. The ‘hh’ blood group is often mistaken as the O group, but while the O group has Antigen H, the hh group does not. Although the lack of Antigen H does not affect the normal parameters of complete blood count (CBC), the rarity of this blood type causes problems to patients with this blood type during a blood transfusion.
