Some genetic conditions occur more frequently among people whose ancestors are from specific geographic locations or religious/cultural groups. Due to either intermarriage or a small gene pool, there is a higher chance that specific genes common to this group will be passed on, including genes which cause specific conditions such as Usher syndrome. Because of this phenomena, Usher syndrome may be more frequently seen in the following ethnic groups:
Ashkenazi Jews - Usher 1f and Usher 3a are currently on the Ashkenazi Jewish genetic panel of 19 diseases for which Jewish couples should be tested if they are planning to have a family. Testing can determine whether individuals are carriers of these genes. If both parents are carriers of the same gene for Usher syndrome, there is a 25% chance of having a child with Usher syndrome in each pregnancy; a 50% chance that their child will inherit one Usher syndrome gene (and therefore be a carrier for Usher syndrome) and a 25% chance that the child will not inherit an Usher gene (will not be affected and will not be a carrier). Learn more about Usher 1f and Usher 3a.
Acadian/French ancestry - Usher 1C is more prevalent in those of French heritage. Individuals with Usher syndrome 1c and carriers of the USH 1c gene migrated to Canada and Louisiana in the United States. Louisiana has a large USH1C community in and around the Lafayette area. Some families have multiple generations of individuals with Usher syndrome.
Finnish Heritage - according to one study, Usher 3A accounts for up to 40% of all Usher syndrome in Finland
Usher 1C - French, French Canadian or Acadian heritage
Usher 1F - Ashkenazi (European) Jewish heritage
USH 3A - Ashkenazi (European) Jewish heritage and Finnish heritage
USH 3B - Amish heritage and anecdotal connection to India
For more information on the different types of Usher syndrome, click here.