Kenya: A massive African DNA project aims to bridge the knowledge gap on mental illness

November 16, 2020 World



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In July 2009, a woman took her husband to the hospital where our colleagues in western Kenya work. He reported that for several years he had been behaving abnormally, sleeping poorly, hearing voices that no one else could hear, and believing that people were talking about him and plotting to harm him.

He was looking for help because he could no longer work. The man was admitted to the inpatient’s Mental Health Unit and was diagnosed with schizophrenia.

Then the man’s daughter came to visit him. His clothes and hair were matted. She described people plotting against her and giving her dirty looks when she walked down the street. He said he was having trouble sleeping. The doctors looked at each other with apprehension: could she too have schizophrenia?

Eventually, her daughter and four other family members were diagnosed with schizophrenia. Although having six members of the same family diagnosed with schizophrenia is unusual, it has long been recognized that mental disorders can run in families. And often members of such families differ in their symptoms.

For reasons we are just beginning to understand, one family member may be diagnosed with schizophrenia and another with bipolar disorder or depression. In Eldoret, Kenya, where this health facility is located, it is not uncommon to have two or three relatives receiving treatment for mental illness.

Such an event is not unique. Research has found that severe mental illness is affected by genes more than any other risk factor. And genes are emerging as important clues for new treatments.

But research on the genetic basis of mental illness has so far largely excluded populations that do not belong to the European heritage. This means that this Kenyan family and other people of African descent may not benefit from the new biological insights into mental illness.

To help remedy this problem in psychiatric research, researchers from the United States and four countries in Africa are working together to study the genetics of schizophrenia and bipolar disorder. They come from the Harvard TH Chan School of Public Health and the Broad Institute of MIT in the United States, Moi University and the KEMRI-Wellcome Trust in Kenya, Makerere University in Uganda and the University of Addis Ababa in Ethiopia. Rounding out Southern Africa is the University of Cape Town team.

The initiative aims to do something that has never been done before on this scale: recruit 35,000 people in Ethiopia, Kenya, South Africa and Uganda to answer questions about their health, lifestyle and mental illness and donate two teaspoons of saliva for DNA testing.

Diversity problem

The discovery that severe and chronic mental illnesses tend to cluster in families has spurred efforts to understand the genetic differences between people with these illnesses and those without. By looking at the DNA and unraveling what is going wrong in the brain to cause these mental disorders, we hope to spur the creation of new drugs to treat these debilitating diseases and reduce the suffering that comes with them.

Unfortunately, recent efforts to study the genetics of a number of diseases have what many of us call a “diversity problem”. Most of the work on human genetics so far has focused on people of Northern European ancestry, distorting the data in a way that makes it less useful for most people in the world.

The world is dangerously close to an era of “white only DNA testing”. In existing databases, 78% of the DNA data comes from people of European descent, who make up only about 16% of the world’s population.

One of the main problems presented by this diversity problem is that any solution (including new drugs) is likely to work best for the people on whom DNA research was based – people of European descent. In fact, most residents in a city as diverse as the US city of Boston, made up of white, black, Hispanic and Asian people among others, may not benefit from research efforts from only a portion of the world’s population.

Potential targets for new drugs

Our great collaborative effort in Africa is called Neuropsychiatric Genetics of African Populations-Psychosis, for short “NeuroGAP-Psychosis”.

With data collected from the 35,000 people recruited for the project, we will look for important and clinically relevant genetic differences that might be found in people of African descent and may be less common in people of European descent.