I have read it in several places... including the CARES web page. Also PENS (ped endo nursing society) booklets but they do not have the booklets on the web but you can order one from the CARES or PENS web pages.

http://www.caresfoundation.org/ethnicity.html

Are Some Ethnic Groups More Prone to NCCAH?
Yes.

Certain ethnic groups are at higher risk for NCCAH. Ashkenazi Jews and Hispanics have higher rates of NCCAH than the general population. For Ashkenazi Jews (Jews whose ancestors came from Eastern Europe), the rate of NCCAH is 1 in 27 people. As many as one-third of all Ashkenazi Jews may carry the gene for NCCAH. For Hispanics, the rate of NCCAH is 1 in 40 people