Factors influencing the frequency of cystic fibrosis in South West Africa.

Drift, chance effect in a small community and consanguinity have resulted in 
South West Africa's high cystic fibrosis incidence. Isolated communities generations ago 
in Europe, e.g. Bad Gastein, where this congress was held, surrounded 
by its Alpine peaks, could have resulted in gene enrichment, which 
together with the increased fertility of the heterozygote could still be 
responsible for most of the CF seen wherever Europeans live today. 
