Mortal Inheritance

Omotola Jalade Ekeinde is perhaps Nigeria’s most famous actress (wasn’t she on the Time 100 list of 2013?) She burst into our national consciousness with the movie Mortal Inheritance although her first film was the memorable Venom of Justice with Ejike Asiegbu.

I watched Mortal Inheritance in 1995/6, in the film she was a young girl with sickle cell anaemia who fell in love with Fred Amata’s character who was a sickle cell disease carrier. From the film I learned about sickle cell anaemia for the first time- I’d always heard the term sickler but I thought it meant a sickly person. I also developed a mid-level crush on Fred Amata but that’s not the point of this post.

Fast forward to October 1998, I’d just gained admission to FGGC Bida and I had to undergo a host of health tests and one of them was the genotype test. My dad and brothers had done the same test earlier that year and they were all AA and it didn’t occur to me that I’d be anything but AA. Imagine my shock and disappointment when the result showed that I was AS. I instantly remembered my mother’s friend who had to break up with her fiancé earlier that year when their church pre marriage tests showed that they were both AS. Naturally she was devastated, they’d been together for years. As young as I was, I was pretty scared about meeting a man when I was older, falling in love and all that jazz only to discover that he was also a carrier.

I resumed school on the fifteenth of October to find the school in mourning. One of the students in SS1 or 2 had died as a result of sickle cell anaemia. Around the same time the next year, her younger sister also died from the disease, when I left that school they had two daughters left there and one of them had the disorder.

Sickle cell disease/anaemia is a haemoglobinopathy- a family of genetic disorders caused by the production of abnormal haemoglobin. Symptoms include painful crises caused by reduced oxygenation of tissues and cells of the bones (usually) and the spleen, lungs and kidneys in some cases, increased susceptibility to infections, bone changes due to bone marrow hyperplasia, hip necrosis. This can be traced to the fact that the abnormal haemoglobin affects the shape, function and life span of Red Blood Cells (RBCs)

Haemoglobin is the iron containing colouring material of RBCs, their function goes beyond adding colour to RBCS, their functions include;
Transport of respiratory gases- oxygen from the lungs form a complex with the haemoglobin in RBCs which dissociates at the tissues and the carbon (IV) oxide from the cells form a complex with the haemoglobin which will dissociate at the lungs. In a nutshell, haemoglobin carries oxygen from the lungs to the tissues and it transports carbon (IV) oxide from the tissues to the lungs
Acts as a buffer in the blood acid-base balance.
In the disorder there’s a mutation (abnormal change) in the gene that controls the production of haemoglobin, due to this mutation there’s a change in the haemoglobin amino acid sequence. The consequence is that at low oxygen concentrations (in the tissues after releasing oxygen) the haemoglobin polymerises (sticks to each other) to form a gel and eventually a fibrous mass that distorts the shape of RBCs.

RBCs are basically the vehicle that conveys haemoglobin from one point to another. It has a distinctive biconvex shape which allows it to;
Have a large surface area for the absorption and removal of substances in and out of the cell
Equal and rapid diffusion of oxygen and other substances into the interior of the cell
Easy passage through the minute capillaries while sustaining little or no damage
Haemoglobin makes up 95% of the dry weight and 30-34% of the wet weight of the cell and it is responsible for the shape of the cell. In this disorder, the abnormal haemoglobin produced causes the RBCs to take the crescent/sickle shape.

The consequence of this is that the advantages by the biconcave shape is lost, the life span is also a lot shorter with the sickled cells having a life span of 20 days while the normal cells last for 120 days. The spleen and bone marrows which are the sites for RBC production cannot supply enough new RBCs to keep up with the demand and the kidneys can’t mop up the byproducts of the accelerated breakdown of RBCS.

The sickle shape of these RBCs confers some protection from malaria due to the fact that the malaria causing organism plasmodium undergoes an essential part of its life cycle in the RBCS. The presence of plasmodium in an RBC will induce a quick lysis (splitting) of the cell, besides the haemoglobin polymer cannot be easily digested by the parasite, perhaps that’s why it is still prevalent in malaria endemic areas.

This disorder is a homozygous recessive disorder, this means that two copies of the gene has to be present for its effect to be seen/expressed. If a person has only one copy of the gene, he is said to be a heterozygous carrier who got the gene from only one parent.

Usually the sickle cell disease sufferer is the child of two carriers. Choosing to have a child with another carrier is highly irresponsible as well as evil and selfish and practically no one would want to venture into it even if the love is as sweet as a Bollywood movie. Every time you watch your child suffer, you’d remember that you could have prevented this pain, when the child wishes he/she was never born (like a twenty nine year old young man I met who came to the hospital for his second hip replacement surgery, the surgery failed and he had to come back the next month, he was the last of four children and the only sickler. He kept crying and asking why his parents brought him here to suffer). Yet the prevalence of sickle cell babies has only reduced slightly, how come?

Laboratory mistakes are the major contributor, I’ve met several couples who got married after erroneous test results had shown that one or both of them were AA only to see something when the child is born. This is capable of breaking up a marriage or estranging a couple. Just before I started my internship, we had to undergo a series of tests and one of them was genotype. The result from the hospital which is a federal hospital and a WHO collaborating center showed I was AA. Let’s imagine that this was the first time I was doing the test, I’d be rejoicing over a false result and would gladly marry a sickle cell carrier. Alas this was my fourth test and the first three were the same, I repeated the test some months later and I was still AS. When it’s time to “settle down” before I accept “his” proposal, we’ll visit various labS of my choosing. I can’t shout!

Do you know your genotype? If you don’t, what are you waiting for?

PS: pictures would have made this post easier to understand but my wordpress for Android is not cooperating.