Genomics is key especially in closed populations: Lithuanian ashkenazi jews and FH

"South African Jews

Ashkenazi Jews in South Africa also have high rates of FH. They are descendants of an estimated 40,000 Jews who arrived in South Africa between 1880 and 1910. They were immigrants from a small geographical area in Lithuania.²² The prevalence of HeFH among Johannesburg's Jews is 1:67.²² The majority had a common mutant allele, a 3-base pair deletion in exon 4 of the LDLR gene²³ called FH-Piscataway. This same mutation has been found in other groups of Ashkenazi Jews around the world who originated from Lithuania.²³ A founder effect is unlikely to have manifested with this large starting population, which suggests the high prevalence of FH stems from a founder mutation in Lithuania.

- See more at: http://www.acc.org/latest-in-cardiology/articles/2015/07/17/08/23/variation-in-the-prevalence-of-familial-hypercholesterolemia-around-the-world#sthash.VKKFaDPY.dpuf"