Professor Adekunle Adekile
As we celebrate this year’s World Sickle Cell Day, Nigerians need to take a pause and appreciate what the disease means to us as nation, in particular and to the Black race, in general. I wonder how many Nigerians are aware that the country is the epicenter of the disease worldwide with the highest prevalence figures. While there are about 300,000 babies born with the disease in the world every year, about half of these are born in Nigeria! Indeed, it is estimated that 2% of all Nigerian newborns are affected by the disease, and about 30% carry the trait.
What is sickle cell disease (SCD)
SCD is a genetic disease affecting the red pigment in our red blood cells, called hemoglobin. It is responsible for carrying the life force, oxygen, from the lungs to all tissues of the body. It is a protein molecule made up of chains of amino acids. The arrangement or sequence of the latter have to be precise for the molecule to function optimally. Mutations that change the amino acid sequence cause different types of hemoglobin disorders. The sickle hemoglobin, HbS, is one of the most common and severe of these variants.
To have the disease, an individual has to inherit 2 copies of the gene, one from each parent. Where the parents are both carriers, there is a 25% chance that they will have an affected baby with each pregnancy and 50% chance of having babies with the trait, i.e. carriers. This is described as autosomal recessive inheritance.
How did the mutation arise?
Genetic mutations occur all the time and the body is armed with mechanisms that eliminate these so that they are not passed on to the next generation. However, some mutations confer a survival advantage to carriers (i.e. those with the trait) and therefore are selected for persistence and are transferred from one generation to the other. The corollary, however is that homozygotes, i.e. those with 2 copies of the mutation usually suffer deleterious effects.
Early human populations were nomadic hunters and gatherers for thousands of years. At this time, transmission of infections was uncommon. However, the onset of the stone age heralded the agriculture-based civilization with people settling along river banks with the establishment of villages and cities. There was massive expansion and increased population density. For the first time, transmission of infections by various vectors became established. One of the earliest and deadliest infections was malaria, transmitted by the mosquito. Individuals with sickle cell trait are protected from complications of malaria and are better able to survive attacks. Because of this survival advantage, the sickle gene became prevalent in any population where the infection was endemic. Unfortunately, the homozygotes, i.e. those with SCD, pay the price for our ability to survive. They are afflicted with many ailments.
How does SCA present?
The red blood cells in the affected children are abnormal and short-lived, hence the patients have anemia. Secondly, these cells tend to be rigid and form clogs within the blood vessels in different parts of the body. This is what produces the recurrent pain crisis that characterizes the disease. The pain can affect any part of the body, but usually the limbs, back and abdomen. The immune system is affected and that is why infections are common and deadly. Other common presentations include stroke, chronic kidney and lung diseases and problems with bones.
Mortality and Management of SCD
The mortality in SCD is very high and in sub-Saharan Africa, many of the affected children do not live to their 5th birthday. The commonest causes of death in early childhood are severe anemia and infections. Hence the management is multidisciplinary with emphasis on early diagnosis, counselling, prevention of infections and comprehensive attention to overall health maintenance. These call for regular follow up and surveillance for possible complications with prompt appropriate interventions. There are also some recent medications that are efficacious in managing the disease. There is a place for blood transfusion, but the only cure is stem cell transplantation. Some breakthroughs are being made in the area of genetic engineering and this may be an option in the future.
Situation in Sub-Saharan Africa (SSA)
Many of the treatments outlined above are not available in resource-poor countries in SSA. Moreover, because of the overwhelming numbers of patients involved, it is very difficult for most governments to provide adequate manpower and other requirements for state-of-art care. In recognizing this fact, the World Health Organization in 2008 declared that SCD has to be considered as a public health priority in affected countries. For this reason, the management has to devolve around public/community health strategies. This is more so in Nigeria and other SSA where most patients live in the rural areas with little or no access to modern health care facilities.
The Nigerian SCD Network/Sickle Cell Support Society if Nigeria
Although there have been many organizations, NGOs and societies that are devoted to SCD advocacy, it was in 2010 that a dedicated team of Nigerian physicians, scientists and other interested individuals got together in to form the Nigerian SCD Network, which has, since morphed into the Sickle Cell Support Society of Nigeria. The objectives of the network were advocacy, capacity building/training and research.
Highlights of Achievements
The network has liaised with the federal and state ministries of health and other stakeholders. We have encouraged government to establish a policy for the management and control of SCD in the country. While a draft policy was presented to the Senate in 2011, this has not progressed much farther. It is noteworthy, however, that some state governments including Kaduna, Delta and Anambra have come up with different policies.
The FMOH has also come out with guidelines for the management of SCD, which are being distributed to healthcare providers in the country. We contributed greatly to this document.
We have supported the efforts of the government to establish newborn screening centers in different parts of the country.
We have encouraged the training of different cadres of personnel in the SCD field. We secured scholarships for a number of young Nigerian physicians to pursue higher degrees in different institutions abroad – 2 received the MSc from University College London, 3 PhDs and 3 MScs from Brazil while some have had fellowships in different US centers. All the graduates have established programs in different centers in the country.
We hold a national conference biannually at which we run training workshops. The latter focus on the training of community health workers and members of the press to empower them in the understanding of the disease so they can provide care and be informed advocates respectively.
The Network now has presence in the 6 geo-political zones of country with active collaborators in more than 20 tertiary and secondary health institutions with established SCD clinics. This has fostered high-level research, many of which have been completed and published in peer-reviewed international journals. We have made presentations at regional and international conferences. Currently we have extensive international collaborations with centers in the US, Brazil and UK. We are partners in an NIH-funded grant in collaboration with Ghana and Tanzania for comprehensive studies of the disease on the African continent.
There is no doubt that Nigeria has regained her leadership role in the field of SCD in Africa and the world. We now have a respected profile, thanks to the dedication and hard work of young Nigerian men and women.
We have a conference coming up next year in Warri, Delta State. The venue was picked, in part, to honor Governor Okowa, who has been a stalwart in the cause of SCD. It was him and his colleague, Hon. Nenadi Usman, who prepared and presented the Draft of a Bill on the Management and Control of SCD when they were in the National Assembly.
The way forward
There is still a lot of work to be done. Emphasis has to be on raising awareness, counselling and newborn screening. Community health workers have to be trained so they can be deployed in rural areas. They should be able to give routine care to SCD patients and identity who needs to be referred to a specialist center for care. Government has to show the political will and commitment to establish a national policy and provide funding and health insurance for these patients.
Lastly, we have to acknowledge the fact that we owe our very survival as the Black race, to a large extent on the sickle gene. Unfortunately, the homozygote patients bear the brunt of this survival. We have to make every sacrifice possible to take care of them. A concerted effort is needed at all levels.
For anyone interested in the work of the network and the SCSSN, we invite you to visit our website: http://www.scsn.com.ng.
I thank all my colleagues in the Network and SCSSN for their hard work and cooperation. In particular, the Vice Chairperson, Prof. Obiageli Nnodu, of the Centre of Excellence in Sickle Cell Disease Research and Training, University of Abuja, has been invaluable in coordinating the activities of the Network in the country.
Professor of Pediatric Hematology
Centre of Excellence in Sickle Cell Disease Research and Training
University of Abuja
Nigerian SCD Network and the Sickle Cell Support Society of Nigeria
At CESRTA, this year’s WSCD celebration was low key with kick off of our school based under five screening program in Gwagwalada. At the end of our afternoon clinic the UATH recently formed SCD Patient Group, the UATH Warriors spring a surprise on us with a celebratory cake baked by one of them.