Are particular people at risk for beta thalassemia?

Yes. Thalassemia is one of the most common gene mutations in the world. Overall, an estimated 20-25 million people are carriers (1/300) (about 1/1000 in low-risk peoples, and about 1/30 in high-risk peoples). Low risk: japanese, korean, n. European caucasians, native canadians, native americans. High risk: mediterranean, middle eastern, south asian, south-east Asian (western pacific rim), caribbean.
Genetic disease. Beta thalassemia is caused by a mutation in the gene that codes for the beta subunit of hemoglobin, the protein that carries oxygen in the bloodstream. The disease is inherited in an autosomal recessive fashion, meaning that an abnormal copy of the gene must be inherited from each parent.