Know Your Blood Group System Rhesus Compatibility Genotype

By | September 23, 2021

Blood group is the classification of bloodbased on the presence or absence of inherited antigenic substances on the surface of Red Blood Cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the Blood Group System. Blood types are inherited and represent contributions from both parents.
The relevance of the Blood Group System Blood groups have a hereditary basis and depend upon a series of alternative genes, a fact sometimes utilized in solving the problems of disputed parentage. They have been used in forensic science and were formerly used to demonstrate the impossibility of paternity (e.g., a type AB man cannot be the father of a type O infant), but both of these uses are being replaced by genetic fingerprinting, which provides greater certainty.


What is the Rhesus Factor?

It is a type of protein found on red blood cells. If you have Rh factor, you’re Rh-positive. If you don’t have it, you’re Rh-negative. Rh factor is inherited (passed from parents to children through the genes). Most people are Rh-positive. Whether you have Rh factor doesn’t affect your general health. However, it can cause problems during pregnancy.

When does Sensitization occur? These antibodies usually don’t cause problems during the first pregnancy. This is because the baby often is born before many of the antibodies develop. However, the antibodies stay in your body once they have formed. Thus, Rh incompatibility is more likely to cause problems in second or later pregnancies (if the baby is Rh-positive). The great problem to avoid with genotype matchmaking for intending couples is Sickle cell disease. Intending couples must make sure to know their genotypes and be sure it’s compatible for marriage before going ahead to get married.

So who can you marry and who shouldn’t you marry based on Genotype compatibility? Someone with the genotype AA can marry across. That is there’s no risk of having a sicklier for a child even when he or she marries an SS. But AA marrying an SS can only result in AS children. There’s no hope of having a child with the genotype AA Someone with the genotype AS should only marry someone with the genotype AA because if AS marries AS there’s one out of 4 chances (AS, AS, AA and SS) that they will have a child with the sickle cell disease. Same applies when AC is combined. AC and AS combine will produce AA, AS, AC, SC, the sickle cell disease will be SC.


The genotype of an organism is the inherited instructions it carries within its genetic code. Genotype simply refers to haemoglobin gene constituents. Genes are always in pairs and overall expression depends whether dominant, recessive or X-Iinked. So there is no problem when one of the genes is abnormal e.g. AS, AC. This is called a carrier state (sickle cell trait). Only when the two are abnormal then there is a great problem. The genotypes in humans are AA, AS, AC, SC, SS. Of course, there are many cases where two abnormal was combined that is an AS and AS or AC and AC or AC and AS couples and had up to five or six children without a single sicklier among them. But why risk it? What if you’re not so lucky? Can you forgive yourself when you end up having a child with the

sickle cell disease and put the child through the agony the disease brings when you could have easily avoided it?

Before saying ” I do” know your blood group and genotype. Help in preventing genetic diseases by marrying a partner of compatible genotype. Do not allow love to override your sense of reasoning. Determine the Rhesus status of every newly-born child.

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