GENETIC COUNSELING AND AMNIOCENTESIS: SALVATION OF THE UNBORN

Numerous scientific research has shown that basically everything about humans are made possible by series of chemical reactions. In a similar way, these chemical reactions are entirely dependent on biological catalysts known as enzymes. Let me break this down a bit. As we all know, the ability of someone to read and understand this article requires the proper functioning of the brain. And for the brain to function properly, several chemical reactions must occur through the help of enzymes. Honestly, I would have loved to explain how this takes place but i won't. Just like my friend would say, "too many sweet gist gives diabetes". So, instead of trying to discuss everything, lets hold on to something.

Well. We've already established the fact that no matter how essential a particular reaction is to an individual's survival, it will never occur without the corresponding enzyme responsible for triggering such reaction. And the scariest thing about inability of a chemical reaction to occur due to the absence of an enzyme is that it may result in a medical disorder. This is the major reason why the deficiency of an enzyme is catastrophic in nature. However, although people know about most enzyme deficiencies, it's only few that knows its root.

The truth is, almost all, if not all enzyme deficiencies can be directly linked to the problem of defective genes. According to Gregor Mendel's work in genetics, the problem with defective genes is that, most times there are inevitable. This is because there are mostly inherited, or caused by mutation. All the same, as we move ahead you'll understand that this situation is only increasingly inescapable because humans have ignored certain measures that would have diminished or to some level bring about a disorder-free-society.

Rather than preventing the deed from happening, the world is relying on newborn screening programs that will only diagnosed the medical disorders after birth, forgetting the fact that prevention is far better than cure. So on that note, the main aim of this article is to elucidate the preventive measures individuals could adopt to save the future generations from the problems of defective genes. Join me as I take you through genetic counseling and amniocentesis, you are sure to learn a lot from this.

Lets start with the basis. Why genetic counseling should be considered paramount...

License: CC BY-SA 3.0, Author: Cburnett, Wikipedia commons

To be very sincere, initially I only wanted to write on amniocentesis. I got so intrigued by this word when I stumbled on it while researching on my last article, the unanswered question about fraternal twin conception. Despite how essential this subject matter is to humanity, I discovered that most people do not know a thing about it. This is because the singles and even those dating feels that genetic counseling isn't for them. Sadly, the married don't also see the need for it either. Funny enough, I once belonged to one of these groups. I promise to succinctly explain amniocentesis after we finish discussing on its forerunner (genetic counseling).

Honestly, marrying someone you love is perfect. But the question is, "are you guys genetically compatible?". In this part of the world, so many individuals have ignored this basis and at the end blame witches and wizards for something they know nothing about. Personally, I believe individuals should make genetic compatibility an important criterion to be considered before accepting to date or even marry a person. Love can then follow. As a matter of fact, genetic compatibility is not only limited to carrying out genotype test to determine sickle cell anaemia. The truth is, majority of people feel they've fulfilled all righteousness just because they've done sickle cell genotype test, not knowing that they still have a long way to go.

Although to some extent it's slightly impossible to determine all the genes that parents pass on to offspring, you'll agree with me that if so many people realized the need to adhere to most of the common principles of heredity used in genetic counseling, the world would have witnessed a tremendous decrease in genetic defects. But since individuals do not appreciate the importance of genetic counseling, they're at the same time ignorant of the impending consequences. That is why there's a great increase in the incidence of genetic defects which has resulted in several medical disorders.

For instance, from the diagram above, a couple might not be anaemic, but there's a possibility of them having a child that suffers from this disorder. This is because both of them have the sickle-cell trait and could be referred to as heterozygous carriers of the recessive allele for sickle cell anemia. Without genetic counseling, there's a tendency for such a couple to face a high risk pregnancy.

Another typical example is the issue of married couples with incompatible Rhesus blood factors. Unfortunately, despite the fact that so many people know their blood group, it's only but a few that are aware of the importance of their Rhesus factor in the choice of a life partner. For example, a man with blood group O (Rhesus positive- RR) might marry a woman with the same blood group but with a negative Rhesus factor (rr) thinking that it's nothing worthy of concern. However, just like agglutination occurs if a Rhesus negative person receives Rhesus positive blood, this type of agglutination reaction also occurs when a Rhesus negative mother gives birth.

Do the crossing and you'll realize that there's a significant probability that all her children will be Rhesus positive. During the first birth, some foetal blood cells leak into the maternal blood circulation causing the mother to develop anti-Rhesus antibodies. Only a small proportion of the foetal blood cells agglutinate in the first child that's why normally they're not affected. Yet, this is not the case for subsequent pregnancies. After having her first child, the woman will start experiencing series of miscarriages due to massive destruction of the foetus red blood cells caused by these anti-Rhesus antibodies.

This might sound unbelievable because in this part of the world people link such situations to spiritual powers. Yet, the truth is that there's nothing spiritual about this. It's just one of those problems that could have been, and can still be prevented through genetic counseling. For those that married out of love and ignored Rhesus incompatibility, this problem can be averted through the help of amniocentesis. The unborn child can be saved by giving it a transfusion of the Rhesus negative blood while it is still in the womb.

What really is the big deal about amniocentesis?

License: CC-BY-SA 4.0, Author: BruceBlaus, Wikicommons

I don't think I'll be making an illogical premise if I term amniocentesis as a preventive measure for medical disorders. The reason why I choose to call it a 'preventive measure' is because it is a prenatal diagnostic technique and there's an incredible chance of saving the foetus from any chromosomal abnormalities that results in defective genes. This is quite unlike newborn screening programs that only aid individuals to manage the disorders after birth.

The entire concept of amniocentesis begins with the removal of some amniotic fluid from a pregnant woman during the fourth month of her pregnancy. Before the amniotic fluid is being removed, the woman must first be administered with a local anaesthetic so that it will relieve the pains felt while the physician insert the needle through the abdominal wall. Now, the interesting thing about this is that the amniotic fluid content basically comprises of discarded skin cells from the foetus. Although at first this technique was mainly for the purpose of fetal sex determination, with time it gradually became necessary for clinical assessment of the well-being of the foetus.

Actually, how amniocentesis is used for the assessment of genetic defects in the foetus is that the discarded cells present in the amniotic fluid are grown in a tissue culture. When this is done, defects like Down's syndrome can be easily detected by merely looking at the cells through a microscope. The reason why Down's syndrome is easily visible is that normally a zygote should have two copies of chromosomes from both parents. But in rare cases, during fertilization, a situation might occur resulting in the possession of three copies by a particular chromosome number 21. From several research studies, such individuals are always mentally retarded (or intellectually disable in mild cases), with typical folded eyelids that gives them a mongoloid appearance. So to avoid this future disaster and unnecessary stress, such pregnancies are usually terminated.

Aside from Down's syndrome, biochemical tests on both the cells and amniotic fluid can reveal other genetic disorders such as phenylketonuria. Just as @kingabesh asserted in his post on Phenylketonuria (PKU), under normal metabolic conditions, phenylalanine, like glucose, is harmless. The problem commences when phenylalanine accumulates due to deficiency of the enzymes phenylalanine hydroxylase and dihydrobiopterin reductase, thereby triggering phenylketonuria in the process. Yet, our emphasis is on the fact that unlike Down's syndrome where the pregnancy is terminated; in cases of phenylketonuria, the child can be saved through amniocentesis. The formation of the excessive substances that affects the brain development of the child can be prevented when the mother is placed on a low phenylalanine diet. Also, after birth, the child must maintain this diet until age six when the brain development is complete.

Final thoughts

Generally, when talking about amniocentesis, most pregnant women are concerned about the risk of miscarriage associated with this diagnostic technique. However, 2006 studies have shown that due to technological advancement, the possibility of miscarriage has greatly reduced to 1 in 1600 cases. Also, some parents choose not to know the fate of their unborn child for so many reasons.

Furthermore, due to legal restrictions in most countries on fetal experimentation; this has barrier advance research on the use of amniocentesis to directly correct defective genes. But like i said earlier, genetic counseling is paramount and should be appreciated.

For further reading...

Wikipedia-amniocentesis. Retrieved on the 28th August, 2018
Pregnancy and amniocentesis. Retrieved on the 28th August, 2018
Amniocentesis: are the risks worth the benefits of this procedure?. Retrieved on the 28th August, 2018

Ramalingam, S. (2011). Modern Biology, 6th Edition. Nigeria: Africana First Publishers Plc, pp. 543-570.

Voet, D., Voet, J. and Pratt, C. (2013). Fundamentals of Biochemistry, 4th Edition. USA: John Wiley & Sons Inc, pp. 740-741.

Image sources
Images are from flickr, pixabay and wikicommons, licensed under creative commons and eligible for commercial use.