An estimated one percent of the U.S. population, or about 2.5 million people, may be carriers of ataxia telangiectasia (A-T). A-T has no racial, economic, geographic or education barriers. Both males and females are equally affected. It is believed that many children with A-T, particularly those who die at a young age, are never properly diagnosed. Therefore, this disease may actually be much more common than projected.
This answer is based on source information from National Cancer Institute.