 Population studies from numerous areas in the world have shown that HHT occurs at roughly the same rate in almost all populations: somewhere around 1 in 5000. In some areas, it is much more common; for instance, in the French region of Haut Jura the rate is 1: 2351 - twice as common as in other populations. This has been attributed to a founder effect, in which a population descending from a small number of ancestors has a high rate of a particular genetic trait because one of these ancestors harbored this trait. In Haut Jura, this has been shown to be the result of a particular ACVRL1 mutation (named c.1112dupG or c.1112 _ 1113insG). The highest rate of HHT is 1: 1331, reported in Bonaire and Curaçao, two islands in the Caribbean belonging to the Netherlands Antilles.
