Wednesday, 21 June 2017

Sicle cell Anemia 101

 Sickle cell anaemia? 
 Sickle cell anaemia (SCA) is an inherited disorder of blood. It is very common in Nigeria, with 3 of every 100 people of the population affected (HbSS) and 1 in every 4 people as carriers (HbAS) of the abnormal gene responsible for the disorder. 

It is a lifetime disorder that is characterized by
recurrent episodes of extreme generalized body pain and the need for blood transfusion (called crisis) and long term complications culminating into decreased quality of life and a lower life expectancy than the general population. The carriers rarely develop symptoms of the disorder however transmit the abnormal gene to their children. Inheritance? With each pregnancy, if both parents are AA, there is a zero chance that the pregnancy will result in a SCA child; if both are AS, there is a 25% chance and if both are SS, it is 100%. These values are probabilities even though there is 25% chance, it is not unheard of AS couples having no SCA child. There is also a long standing misinterpretation of these values in which for instance, the AS couples are erroneously predicted to have a quarter (25%) of the total number of their children with the disorder. These values are not that extensive, they simply depict the odds with each pregnancy. 

 The sickle cell genes are inherited from both parents. No single parent is singularly responsible for any SCA child. Apportioning blame is completely irrational and is only disruptive to the family and completely unhelpful. Knowing Your Genotype? The importance of knowing your genotype cannot be over emphasized. Knowing your genotype does not preclude you from marrying anyone you love. It simply offers you the chance of choice. You can choose to take the risk of having a SCA child or not. If you choose to take the risk, the fact that it is your choice prepares you psychologically and allows you to take decisions and plan ahead for all eventualities. Caring for the SCA child exerts enormous strain on the parents psychologically, emotionally, socially, financially and physically. The parents are in constant anxiety about the wellbeing of their child, emotionally distressed as they witness helplessly the sufferings of their beloved, frequent disruption of personal, family and occupational activities by frequent hospital visits and admissions and the burden of recurring medical expenses. 

 To the unwary and unprepared, these stresses are unbearable with resultant clinical depression, guilt, family disharmony and stress-related personal health problems. The genotype test is cheap and widely available. Know your genotype and make your choice. The best time to know your genotype is before you start any relationship and it is wise to know your prospect’s genotype before things get any serious. Prenatal Diagnosis? SCA can be diagnosed before birth (prenatal diagnosis). Prenatal diagnosis is relevant only when (i) there is a background risk of SCA e.g. AS couples (ii) the couples are willing to terminate any pregnancy with unfavorable outcome. Different tests are available for prenatal diagnosis of SCA. These include: chorionic villus sampling, amniocentesis, fetal blood sampling etc. Chorionic villus sampling can be used to diagnose SCA as early as 10th week of pregnancy i.e. even before pregnancy is obvious and there is minimal maternal emotional and/or psychological attachment to the growing fetus, thus significantly eliminating the dilemma of pregnancy termination. 
                          Is there a Cure? 
 The only available possible cure is bone marrow transplant (BMT)/ stem cell transplant (SCT). This procedure is high risk, very expensive (averaging about twenty five million naira) and currently not available in Nigeria. Both adults and children can benefit from the procedure but the younger the best the outcome and the less the risk. 

Even though BMT/SCT offers cure to the SCA individuals, it does not eliminate the chance of transmitting the abnormal gene to their children. Other available medical therapies aim to decrease the frequency and severity of crisis, prevent complications and improve the quality of life. 
However the best medicine available is knowledge of the disorder, knowing the triggers of crisis and avoiding them, seeking and adhering to medical counsel. With positive attitude and vigilance from both parents and SCA child/individual, and control of the disorder, SCA individuals are known to live a highly productive and near normal life. 

 You have a responsibility to your progeny. Know your genotype now. Be enlightened and enlighten others. #WorldSickleCellDay


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