Dr Julie Makani is a Clinical Research Fellow in the Nuffield Department of Medicine and is based in the Department of Haematology and Blood Transfusion at Muhimbili University of Health and Allied Sciences (www.muhas.ac.tz), which is the main clinical, academic and research centre in Tanzania.
What is Sickle Cell Disease?
It is an inherited blood disease that affects the red blood cells. There is a wide spectrum of symptoms despite the fact that it is exactly the same genetic mutation that causes SCD – some people are completely asymptomatic and walk around hardly knowing they’ve got the disease, while others are very unwell from childhood and are at much greater risk of dying young.
If SCD is reported to be the single most important genetic cause of childhood mortality worldwide, and is predominantly an African problem, why have virtually no systematic studies been conducted in Africa?
In Tanzania, SCD hadn’t been on the agenda until recently, because quite rightly the government wanted to tackle the problem of infections such as HIV, TB and malaria. As improvements have been seen in reducing the burden of these conditions, the contribution of non-infectious diseases to morbidity and mortality is increasing. Tanzania has developed a strategy for non-communicable diseases and has included SCD as a priority condition. Much of what is known about SCD is from research in the US where 1 per cent of the world’s cases of SCD live, while little is known about SCD in Africa, where over 75 per cent of individuals with SCD live. If we were able to implement effective interventions in Africa it would have a huge public health impact.
Why is the mortality rate for African children born with SCD so high compared to the US, for example?
The US introduced a newborn screening programme to identify all children with SCD at birth; along with a comprehensive programme of healthcare for those affected, which reduced the mortality rate in under fives from SCD by over 70 per cent. Prevention of infection by pneumococcal vaccine and oral penicillin are commonly used to prevent infections in SCD. These are currently available in most African countries, and could be used to help reduce mortality in SCD right now if governments would take action. Newborn screening programmes are more expensive, but they have done it in Brazil. It is more cost-effective to identify the children at risk early and prevent complications.
How can SCD be a model to understand the relationship of genes, environment and disease on a global scale, which could help scientists understand other types of genetic disorders?
If we can find a cure for a single-gene disorder such as SCD, this could be a model for curing other diseases with a more complex genetic basis such as cancers, diabetes mellitus and Alzheimer’s. Even with infectious conditions like malaria and HIV, some people are more genetically susceptible to becoming infected or experiencing more serious symptoms. We also want to better understand how environmental and lifestyle factors can increase your likelihood of developing genetic diseases and learn how to modify or reduce the impact of symptoms. In the future we will see more targeted, personalised medicines being developed to treat people with the same genetic mutation, but tailored to adapt to different environmental, geographic and lifestyle factors.
How important was The Royal Society Pfizer Award in 2011 for raising the profile of the SCD project and the status of African scientific research?
The award has had a significant impact for us as it has raised awareness that it is possible for scientists in low-income countries in Africa to conduct scientific research in disciplines that are considered ‘high-technology’ such as genetics. Scientists in Africa have to spend time doing public engagement, promoting science to public and government, which takes away time from the research. Recognition by the Royal Society and awards such as the Pfizer has been very important for raising our project’s profile and that of science generally.
What would you like to have achieved in five years time?
I hope to ‘retire’ in five to seven years, so I have started to work on a succession plan to make sure that there is a critical mass of people and leaders in the four areas of our work – healthcare, advocacy, research and training. If we can find a greater range of genetic or non-genetic targets for drugs to improve quality of life and reduce mortality that would also be fantastic, and not unrealistic within five years. SCD was first described 100 years ago, so I would hate to think it would be another 100 years before we found the solution to treating this disease.