23/08/2026
The Genetic History Hidden in Afrikaner Family Trees 🦉
For more than three centuries, the descendants of the first European settlers at the Cape have carried something invisible through their family trees. Certain inherited conditions became unusually common among Afrikaners, and in 1983 two South African geneticists published a study showing how genealogy could help explain why.
Professor M. C. Botha and Professor P. Beighton examined the genetic history of the Afrikaner population in the South African Medical Journal. Their research found that conditions including familial hypercholesterolaemia, Huntington’s disease, porphyria variegata, Gaucher disease, cystic fibrosis and familial colonic polyposis occurred at unusually high frequencies.
The explanation began with the small population that developed at the Cape after the arrival of the Dutch in 1652.
The settlers were joined by Germans and French Huguenots, with smaller contributions from other European and non European communities. The population then grew remarkably quickly. Historical records cited by the researchers show that the permanent settler population increased from about 1000 people in 1691 to more than 13 000 a century later.
That growth came largely from the descendants of the original settlers rather than from a constant stream of new immigrants.
This mattered genetically. When a population begins with relatively few founders, a particular genetic variant carried by one of them can become much more common among later generations. This is known as the founder effect. Isolation and marriage within relatively small communities could increase the frequency even further.
Some of the family histories examined by Botha and Beighton stretch back to the earliest generations at the Cape.
One example was Huntington’s disease. About 250 affected Afrikaners had been identified during a South African survey, and around 80 percent of them belonged to just 50 families. Genealogical research connected these families through four large ancestral lines reaching back 14 generations to a Dutch settler who arrived at the Cape in 1652 and the German woman he married in 1668.
Porphyria variegata produced an even more striking genealogical trail. The researchers traced numerous cases to a marriage in 1668 between a Dutch immigrant from Deventer and a Dutch orphan girl from Rotterdam. Their descendants spread eastward from the Cape and later northward as Afrikaner communities moved into the interior.
Another condition, progressive familial heart block, was traced through particular Cape families. One of the affected lines originated with a Portuguese immigrant who arrived at the Cape in 1696 and married a woman of French descent. Another could be traced to a Dutch immigrant from Amersfoort who arrived in 1713.
Familial hypercholesterolaemia was also unusually common among Afrikaners. The inherited condition causes very high cholesterol and can lead to serious coronary artery disease at a relatively young age. The researchers found evidence of the condition in numerous Afrikaans speaking families and investigated the possibility that religious and social isolation had contributed to its prevalence.
Cystic fibrosis presented another remarkable case. Among Afrikaners in South West Africa, the study estimated that about one in every 635 newborn babies was affected. Genealogical research suggested that the high frequency was associated with the small, relatively isolated communities formed by migrants from areas such as Calvinia and Namaqualand.
Gaucher disease was also found among Afrikaners at a higher frequency than would normally have been expected. The researchers could not determine where the genetic variant originated. They considered both the possibility of an early immigrant source and the possibility that it arose through mutation in an early Dutch or Afrikaner ancestor.
The study showed how closely medical genetics and genealogy could be connected. A family tree was not simply a record of who married whom and who descended from whom. It could also reveal how a genetic condition had travelled through generations and across the country.
The Afrikaner population had expanded from a relatively small founding community into millions of descendants. As families moved from the Cape into the Eastern Cape and later northwards, the genes carried by their ancestors travelled with them.
More than 300 years later, researchers were able to follow some of those genetic trails back to individual couples living at the Cape in the 17th and 18th centuries.
For genealogists, it is an extraordinary reminder that an old family tree can contain information far beyond names and dates. Sometimes, hidden among generations of ancestors, it can tell the story of how a genetic condition travelled across South Africa.
