Association between familial hypercholesterolaemia and church affiliation. Is this the result of sociocultural isolation of migrant farmers in 19th-century South Africa?

The family trees of 57 Afrikaans -speaking familial hypercholesterolaemia (FH) index cases were traced to look for founder surnames, for an association between FH and affiliation to the Gereformeerde Kerk (GK), and for consanguinity. Two possible founder surnames were identified. Each occurred in more than 5% of individuals and both were well known among the founders of the GK. Affiliation to the GK was much more common in our sample (45% of 994 individuals) than in the general population (5%), an overall odds ratio of 7,38. This association was stronger in older generations. There were 21 consanguineous marriages, the two suspected founder surnames and affiliation to the GK featuring prominently among them.