Lars Anderson wrote a very accessible article on APOB prevalence in Europe and Lancaster, PA

This Regeneron funded study cherry-picked precisely a region dominated by whites of European descent, and in a region famously influenced by founder effect.  In fact a segment of this population group “probably has the highest incidence [of the R3500Q APOB mutation] worldwide.” The emphasis is mine.

Investigators have detected the R3500Q mutations in over thirty countries worldwide, with a high concentration of carriers in central and northern Europe. Switzerland, Germany, the Czech Republic, and Slovenia are thus areas with a high prevalence of R3500Q,22-25 but the area that probably has the highest incidence worldwide is not in Europe, but in our own Lancaster County, Pennsylvania. In 2010, population screening of members of the Old Order Amish community revealed that approximately 12% of the general Amish population carries R3500Q. This rate is consistent with a genetic “founder effect,” whereby a population bottleneck reduces genetic diversity and increases the frequency of otherwise rare alleles. As the authors of the 2010 study observe, the mutation was likely carried to Lancaster County by one of three hundred German-speaking Swiss members of the Old Order Amish Church. The gene flow rate of R3500Q into the wider Lancaster County community and its incidence among Lancastrians of Mennonite or Germanic heritage is at the moment undetermined. Still, other recessive genetic disorders associated with the Amish have previously been found in non-Amish Lancastrians, and all newborns in the state are screened for diseases associated with the Amish such as glutaric aciduria and maple syrup urine disease. As an analogous yet dominantly inherited disorder, the effect of FDB due to R3500Q on countywide health has considerable significance for the ongoing Lancaster General Health Familial Hypercholesterolemia Initiative. ~ Familial Defective Apolipoprotein B-100 in Lancaster County and Beyond Lars Andersen, B.A. Research assistant and site coordinator for CASCADE FH Registry The Heart & Vascular Institute.