Take a genetic test before saying "I do"…"

 

By Samuel Baker Obakiro

 

Many times before people agree to marry or get married, several qualities (factors) are considered to ensure that the right companion is selected among the many. As such, people make expensive investments and sacrifices before marriage expecting to start and have happy families.

Unfortunately, the happiness enjoyed may only last a short while and depression sets in for the entire marriage life. The extent of depression may be so severe that some victims even start regretting that day they said "I do". Some of the most challenging situations encountered is when a couple fails to produce a child, produces only one child, produces children of only one sex, produces a child with genetic disease (abnormality) like albinism, sickle cell anaemia, haemophilia, experiences spontaneous abortions and premature birth and when a couple produces children with poor genetic characteristics such as high susceptibility to diseases, low academic potential and low hybrid vigour.

To mitigate some of these uncertainties, the victims either try to produce children from outside their legal marriage or they seek God's intervention. To make matters worse, many believe that these challenges arise as a result of one being cursed by ancestors or bewitched. As a result, people who believe in this myth seek solutions from witch doctors and traditional healers from where they are either conned or even risk their lives. This does not only cause family instabilities, but may also ruin one's reputation in the community.  

But what could be the scientific cause of these misfortunes in life?

One explanation lies in genetic incompatibility. This simply means that presence of a given gene in the male gametes (sperms) or zygote formed from these gametes will not give rise to fertile offspring. Thus this results into the mother's body producing chemicals (antibodies) that kill either the gamete or zygote. If the sperms die within the female reproductive tract, then no fertilization can occur and as a result, no fertilisation takes place.

On the other hand, sometimes fertilisation occurs, but the formed zygote is killed by the mother's immune system after her body perceiving the zygote as a foreign organism due to presence of an incompatible gene in the zygote. If such a zygote is not killed, it will be spontaneously aborted out of the female body as a mechanism of getting rid of the incompatible gene.

Surprisingly, in some cases of genetic incompatibility, the baby is even born at the end of the gestation period but fails to grow to maturity and hence dies during child hood. Of late, there is an increase in the number of premature births in the country as evidenced from a high patient load in hospital nurseries. This can be attributed to either increase in cases of genetic incompatibility among couples or interaction of the genes and the environment.

"I produced five children, 3 boys and 2 girls but I am now left with only one after the others each passing away before their 18^th birthday, I am not even sure whether the remaining one is going to survive……"one victim narrates.

The most common form of gene incompatiblilty is the one which is due to the rhesus factor (antigen D). This results into a rhesus negative woman who is married to rhesus positive man producing only one or two children. The subsequent rhesus positive fetuses are killed by the antibody d produced by the mother's immune system upon sensitization by the antigen of the previous rhesus positive babies. However, this condition can be prevented and treated if detected early or before pregnancy.

As you may be aware that the sex of a child depends on the type of sperm (whether X or Y chromosome carrying sperm) that fertilizes the female egg (always carries X chromosome). It therefore implies that it is the father who is responsible for the sex of the children of that couple. However, producing one sex may be as a result of the female body rejecting pregnancy of a given sex due to possession of an incompatible gene. Therefore, every time a zygote of that sex is formed, it is spontaneously aborted while the compatible sex survives and is born. Secondly, sometimes the female reproductive system may due to incompatibility preferentially capacitate(activate) one type of sperm (either X or Y) to the other such that every time fertilization takes place that sex is produced.

An explanation for birth of children with genetic disorders may be due to both parents being heterozygous (carriers) of particular trait. Although themselves are normal, some of their gametes may contain these internal factors which during fertilization may combine and give rise to an offspring with a genetic disease.

But is there a way of predicting and avoiding the occurrence of these misfortunes?

The solution lies in genetic testing and counseling. Genetic counseling is the process by which specialists (genetic counsellors) advise patients and people at risk of suffering from genetic disorders or their children about the effects of the disease, probability of developing or transmitting it, and available preventive and management options. This process involves 1) careful analysis of the family and medical histories to ascertain the chance of genetic disease occurrence in the family, 2) sensitizing the clients about the testing, prevention and management services available and 3) counseling the clients at risk to make informed marital choices and 4) the victims to promote adaptation (positive living) to the risk or condition.

Genetic testing in this context refers to a series of molecular tests involving DNA with an aim of establishing the genetic makeup of an individual so as to identify presence of predictors for incompatibility. Due to negative consequences of genetic incompatibility, it is therefore important that as you request to test your spouse for HIV and other conditions you also perform a genetic test for compatibility. The test may be expensive to conduct but may be lifesaving in the event that the two partners are genetically incompatible

 

The writer is assistant lecturer