Something New Out of Africa: Cystic Fibrosis Affects All Peoples
By Tony Westwood , MBChB, MD & Michele Ramsay, PhD

Southern African connections with cystic fibrosis (CF) go back to the 1950’s. Dr Peter Catzel, who had worked with Dr Shwachman from Boston, USA, looked for CF in black African children in Johannesburg in 1958 using Dr Shwachman’s ‘finger print’ sweat test. No tested child had CF. Indeed, until very recently, CF in black Africans seemed to be so rare that only individual cases from South Africa, Kenya, Senegal and Cameroon had been written up in the medical literature.

Southern Africa is peopled by groups with very different origins. The majority of the black population comes from the so-called Bantu expansion from central Africa between 1000 and 3000 years ago. The groups who traveled furthest South such as the Xhosa-speakers acquired an admixture of genes from the indigenous southern African peoples, the Khoi Khoi and San. The Khoi Khoi and San themselves retreated from or mixed with the European settlers at the Cape of Good Hope in the 17th and 18th centuries. Those who mixed with Europeans or their slaves from the Far East and East and West Africa became the so-called “coloured” group of southern Africa, the majority of whom live in and around Cape Town. The first European settlers (“whites”) were from the Netherlands, Britain and France. Later arrivals were from Germany, especially those who settled in South West Africa (now Namibia), as well as Portugal and Eastern Europe.

Red Cross Hospital’s CF team

CF in southern Africa was first studied in detail by Dr. Maurice Super in the 1960s and 1970s. Among the cases he described (mostly Afrikaners from Namibia) were a few coloured children and a possible black African case. The latter could not be confirmed as no sweat test had been done. That CF was relatively common in the coloured group was demonstrated by Dr. Ivor Hill and colleagues in Cape Town in 1988. In this group they estimated that 1 in 12000 babies born would have CF compared with 1 in 2000 for white people.

Soon after the CFTR gene was identified in 1989, researchers from Johannesburg and Cape Town showed that the deltaF508 mutation was much less common in the coloured CF patients (53% of mutations) than among the whites (82%).

During the early 1990s a number of black African children with CF were diagnosed around South Africa. Mutation analysis proved that they had CF at a genetic level; one mutation, 3120+1G)A (3120) was present in 5 out of the 8 CFTR mutations in the first 4 chilDr.en tested. This mutation had been described among African American people with typical CF and was thought to have originated in West Africa.

The discovery of 3120 in southern Africa led to two further advances in knowledge. Firstly, this mutation proved to be the second most common mutation in coloured CF patients (after deltaF508). Researchers in Johannesburg are now trying to determine if the origin of the 3120 mutation is the same as the one found in the black CF children. Secondly, by testing blood samples from people from a number of African chiefdoms, it has been shown that carriers of the 3120 mutation are surprisingly common: around 1 in 90 healthy black persons carry this mutation! With this carrier rate and the presence of other mutations, over 1000 black African babies with CF are expected to be born each year in South Africa.

While the identification of new cases of CF among black children has certainly accelerated in South Africa from the late 1990s to the present (and these children have the same clinical features as their counterparts in northern countries), their numbers are very low compared to the number expected. Some have suggested that the ‘missing’ CF children are dying in early infancy, labeled as having tuberculosis, malnutrition or even AIDS. While this is possible in under-serviced rural areas, it is most unlikely in well-serviced urban areas such as Johannesburg and Cape Town. This important and intriguing mystery remains.

Red Cross Children’s Hospital in Cape Town

There are about 500 people known to have CF in South Africa. CF services exist in the main centres in South Africa, usually at teaching hospitals. Thus, dedicated clinics for children, adolescents and adults with CF are found in Pretoria, Johannesburg, Cape Town, Port Elizabeth and Durban. Care is often shared with family doctors and paediatricians. Efforts to provide the best possible care for CF patients are coordinated through a group of dedicated doctors and scientists who meet at least three times a year under the auspices of the South African Cystic Fibrosis Association. A CF Symposium is held every two years.

Where do we stand now in southern Africa? Recent estimates show that CF among white South Africans is as common as it is in northern Europe (1 in 3000 births). New figures for the coloured group suggest that about 1 in 10000 babies has CF. In Cape Town about equal numbers of white and coloured CF patients attend CF Clinics – a change from the white predominance of the 1970s and 1980s resulting from better identification of coloured CF patients. CF Clinics now have growing numbers of black patients. Every effort is being made to alert health workers to the presence of CF in all peoples in southern Africa.

And the rest of sub-Saharan Africa? Very little is known. It is hoped that the research and experiences in South Africa will help us to understand the place of CF in the rest of Africa.