New schizophrenia study focuses on Africans

The exclusion of people of African descent in studies of schizophrenia in the past has resulted in a large African genetic pool being unexplored, leading to potential gaps in our knowledge of the disorder.

To remedy this situation, a group of Eastern Cape researchers recently completed the first phase in a study on schizophrenia among Africans and the genetic mutations which predispose people to the disorder.

The research started with Xhosa people in the Eastern Cape, but will be extended to other African ethnic groups.

One of the researchers, Walter Sisulu University professor Zukiswa Zingela, said: “The studies into schizophrenia that have been done previously are based on Caucasian and Asian genetics, leaving a large African genetic pool unexplored.”

Zingela, who heads the university’s department of psychiatry and behavioural sciences, said the findings thus far supported existing theories about the chemical pathways and disturbances in brain function that contribute to the development of schizophrenia worldwide.

“This study does not mean Xhosa people are more prone to schizophrenia or that their ethnicity makes them genetically different to other ethnic groups.

“The study just so happened to be based on Xhosa people because the people who came up with it are  based in the Eastern Cape — it could have been the Sotho, Zulu or Afrikaans communities, depending on the location,” Zingela said.

She and fellow Walter Sisulu University lecturer Mo Nagdee collaborated with researchers from Rhodes University, the University of Cape Town, the  University of Washington, Columbia University in New York and the University of Pennsylvania.

Zingela said the knowledge most scientists had gleaned on the genetic abnormalities that occur in schizophrenic patients was derived from studies done on Caucasians and Asians.

“So what we know is that those studies lack the African gene and our study that we’ve recently conducted in the Eastern Cape was to ensure the rich African gene is also included.

“This is important because most people who make up communities in European countries came from Africa but only a small pool of genetic material went with them, while the rest remained in Africa.”

She said the inclusion of African genes in the study had allowed researchers to determine the differences between people with schizophrenia and those not affected by the disorder by studying a smaller sample, due to a larger genetic variation among Africans.

The study was conducted in clinics in East London, Makhanda, Port Elizabeth and Komani  among  909 Xhosa people with schizophrenia and 917 people without the disorder (controls).

“This is just the beginning because we have made a realisation that we as scientists who have been studying not just schizophrenia but many other illnesses have missed out on the diversity that is provided by the African genetic pool and that, unfortunately, has left us blind to some of the potential discoveries about causes linked to genetic differences,” Zingela said.

Zingela said extensive explorations of diverse genetics would be beneficial to the ultimate goal of preventing illnesses from occurring in the first place by targeting exactly where abnormalities appear.

“We need to have more and more people with greater genetic variations in order for us to say we know enough about what goes wrong,” she said.

Zingela said the research was partly inspired by late UCT professor Bongani Mayosi, who advocated for collaboration between well-resourced universities and those which are historically disadvantaged.

“Born and bred in the Eastern Cape, Prof Mayosi became a world leader in research and he always encouraged clinicians to marry their work with research — that they must use what they learn in their field and communities and combine it with research,” Zingela said.