An article in the New York Times discusses how recessive genes are very common in regional groups; this is due to the founders effect. These recessive genes are expressed when the child receives the mutated gene from both parents which is much more common in regional groups since they participate in consanguineous mating. The Vysva population has a gene mutation which causes a bad reaction to muscle relaxants, Ashkenzai Jews are susceptible to Gaucher disease and cystic fibrosis, and congenital nephrotic syndrome is prevalent in the Finns population. The mutations range from not harmful to terminal which creates a higher than average mortality rate. Recording data about these diseases is important because it allows for prenatal and premarital screenings. These screenings have been used within the Ashkenazi Jew population and has basically eliminated new cases of Tay-sachs disease in the population. These populations provide opportunities to study how genes manifest naturally in humans. It is important to research even the rarest diseases because these mutations can be inherited even if you do not marry your first cousin, some bloodlines simply have a higher risk for certain mutations.