What's the rate of incidence for ataxia telangiectasia?

Ataxia telangiectasia (AT) is a rare disease. Worldwide, the incidence ranges from one person in every 40,000 to one in 100,000. Two factors may play a role in these uncertain statistics. First, the disease rate may be higher in countries where childbearing between relatives is more customary, because relatives are more likely to share common genes. Second, ataxia - loss of muscle coordination - generally causes the earliest symptoms, so someone with AT may be incorrectly diagnosed with cerebral palsy rather than AT.