International Journal of Health Sciences and Research www.ijhsr.org ISSN: 2249-9571 Review Article Bombay Blood Group: A Distinct Descent Samarpita Pramanik Senior Tutor, School of Nursing, Christian Hospital Berhampur, Odisha. ABSTRACT In the field of medical sciences, the Bombay blood group (oh/hh) is a rare yet evolving entity. The „oh‟ blood group has distinct genotype and phenotype characteristics. This article explores the dynamics involved in the Bombay blood group, presenting its epidemiology, phenotype, genotype, biochemistry distribution, clinical manifestations and management. Key Words - Bombay blood group, Phenotype, Genotype, hh blood group INTRODUCTION DEFINITION Blood, a connective tissue is The Bombay blood group is a rare inevitable for human existence. It is vital to blood group which is characterized by the save the lives of patients. The blood absence of A, B and H antigens in the red components are very expensive and rare as blood cell surfaces. It is known as the hh its process and storage is limited due to its blood group or the” Oh” blood group. (2) short viability. In spite of this being rare, improper matching of blood group has HISTORICAL BACKGROUND always been one of the leading causes of It was first discovered by Dr. Y.M. blood transfusion related mortality. Blood Bhende C. K. Deshpande and H.M Bhaia of group as per the encyclopedia of Genetics, the Seth gordhandas Sunderdas Medical 2008 is defined as the basis of chemical College in Bombay (Mumbai) in 1952 who present on the surface of blood cells which first spelt it as Bombay. (1) Thus, it is called are involved in cell recognition. A particular as the Bombay Blood group. blood group (blood types) dictates the presence or absence of antigens inherited THE ‘H’ ANTIGEN from either parent onto the surface of red Karl Landsteiner in his discovery of blood cells. the famous ABO blood types identified that So far, 36 blood group substances the red blood cells have an “H” antigen on are recognized by the International society their cell surfaces. for blood transfusion. The most common are This H antigen is the precursor of A ABO and Rh which help in determining an & B antigens. This H antigen is modified individual‟s blood group and to match the into “A” or “B” antigen like wise and the compatibility for blood transfusion. But the individual get either “A” ,”B” or “AB” real challenges lie in identifying the rare blood group. This modification occurs in the blood group among human population and presence of a Transferase Enzyme. If this intervene promptly for their survival in enzyme is lacking, then the “H “antigen is times of need. not modified and these individuals have the “O” blood group. (5-7) International Journal of Health Sciences & Research (www.ijhsr.org) 251 Vol.9; Issue: 1; January 2019 Samarpita Pramanik. Bombay Blood Group: A Distinct Descent H H H H Transferase A H enzyme RBC E RBC H E H A H H A „A‟ blood group – „A‟ antigen Has Anti B and Anti H antibody B B H „B‟ blood group has B antigen Has Anti A and Anti H antibody RBC H B H B H A „AB‟ blood group has A and B antigen RBC Has Anti H antibody A H B H „O‟ blood group has no antigen Has Anti A and Anti B antibody H H RBC H H H Transferase h h Enzyme h h h h RBC RBC h h h h h h Bombay blood group- has „h” Antigen Has Anti A, B, H antibodies. Figure 1. Diagramatic representation of the ABO and the Bombay Blood Groups International Journal of Health Sciences & Research (www.ijhsr.org) 252 Vol.9; Issue: 1; January 2019 Samarpita Pramanik. Bombay Blood Group: A Distinct Descent But if an individual doesn‟t have the “H” Genotype: According to Wikipedia. (10,11) it antigen but has the Recessive “h” antigen on is the genetic makeup of an individual. It is its cell surface; then such individuals though an organism‟s full hereditary information. It they may have the Transferase Enzyme the determines how much an individual is antigen won‟t be converted into “A,B, different within a group of individuals. So, AB,O” blood groups. Such individual will in Genotype we try to identify what rather develop antibodies against “A, B” combination of genes the individual actually antigens to protect themselves. The probable has. Thus, in an organism, the genotype is reason for this exception is due to the the major influencing factor in the production of an inactivated enzyme which development of its phenotype. is incapable of producing H antigen. Example:-If an individual has a genotype of Aa type; it means EPIDEMIOLOGY A - Dominant Genotype while a- When Bombay blood group is Recessive Genotype. misdiagnosed, fatal hemolytic transfusion reactions occur It is one of the rarest blood BOMBAY BLOOD GROUP groups, present in about 0.0004% (0.4 GENOTYPE-PHENOTYPE million) in the human population. In India, DISTRIBUTION the incidence is 1 in every 7,600 population In blood groups, the “H” Antigen is (8) but, while latest statistics by Suraci et al. the precursor of A and B Antigens. This is (9) stated that this type of blood group is the dominant genotype whereas the “h” found in Southeast Asia. The incidence in antigen is the recessive genotype. this region is 1/10,000 and in Caucasians 1/ Individuals with A and B blood groups have 2,50,000 cases. A high level of two types of antigen on their cell surface. (8) consanguinity presents among the parents of It is similar to like building two storey the Bombay phenotype. building on the cell surface of the RBC‟s. This rare blood group is commonly seen in The first storey consist of the “H” antigen the tribal population of India; most while the second storey in the presence of commonly, in Maharastra, Odisha, Transferase Enzyme either contains “A”, Karnataka, Andhra Pradesh and Tamil. “B” or the combination of both respectively. The second storey represents the blood BIOCHEMISTRY OF BLOOD group which the individual has. In Homo Sapiens, both the parents In individual with “O” blood group, contribute to the formation of a child‟s they do have only one storey building where blood group. The alleles which contribute to they have only the “H” antigen on their cell this are O, A and B. Thus, to know the surface. They do not have a second storey blood type of a child we need to know the expressing any allele as they lack the Phenotype and the Genotype of the Couple. Tranfersase Enzyme. In individuals, with Bombay Blood Group they express the Phenotype: This is the outward physical recessive form of the “H” antigen that is the manifestation of an individual. It is an “h” antigen on their cell surface for which organism‟s ACTUAL observed properties they can not express any other allele of such as morphology, development or either A or B even in the presence of the behaviour. (3) This results from the Transferase enzyme. (12) expression of an organism‟s genes as well Thus, individuals with “O” blood as the influence of environmental factors group and the “Bombay Blood” group do and the interaction between the two. Thus, look similar phenotypically as both of them Phenotype = Genotype + Environmental do not have any antigen of A, or B on their Factors. cell surface. This allows the health professionals to miss the Bombay Blood International Journal of Health Sciences & Research (www.ijhsr.org) 253 Vol.9; Issue: 1; January 2019 Samarpita Pramanik. Bombay Blood Group: A Distinct Descent group cases considering them as “O” blood while the “Bombay Blood” group has the groups. The difference can only be recessive „h” antigen. identified when we assess theses individuals Example:- based on their genotype where the “O” Child looks like having O blood group But, blood group has the dominant “H” antigen actually Child has the Bombay Blood Group PHENOTYPICALY GENOTYPICALY Mother Father Mother Father A B Hh Hh O hh Figure 2: Genotype- Phenotype variation in Bombay blood group (Source: O’Neill,2012) CLINICAL MANIFESTATIONS:- Regular camps need to be conducted to Patients with Bombay Blood Group identify individuals with the rare blood are generally asymptomatic. As they do not group in the nearby community. have any antigen on their cell surface, such There should be proper communication individuals can easily donate blood to any among the various Blood banks at the other individual of the ABO blood group District and State level for such a rare system unless some other blood factor genes blood donor unit in times of need. such as Rhesus factor is incompatible. But, There should be regular screening of the the challenge arises in case these individuals nearby relatives of the Bombay Blood require blood transfusions. In such cases, group individual so as to identify a new these individuals develop severe hemolytic one. reactions if they receive blood from other Because for an individual to be Bombay blood group individuals including O blood Blood group, both the parents need to group. These individuals have antibodies carry the recessive “h” antigen to against A,B, and H antigens; so they can transmit it to their children; so, the receive blood ONLY from individuals who prevalence of having a Bombay Blood have the Bombay Blood group which is a group increases in closed off rare commodity. communities where consanguineous marriage is very common. Thus, proper MANAGEMENT:- screening among such family‟s needs to Bombay Blood group; being a rare blood be done.