<prompt> A couple, with a family history of beta thalassemia major in a distant relative, has come for counseling. The husband has HbA2 of 4.8 and the wife has HbA2 of 2.3. The risk of having a child with beta thalassemia major is:502550  <response>: - Normal percentage of HbA2 ranges from 1.5 to 3. - In thalassemia trait b thalassemia minor, HbA2 level may be elevated 3.5-7.5. - Thus, wife in this question has normal genotype b,b whereas husband has thalassemia - trait b,b. - b-Thalassemia is an autosomal recessive disease. So, None of the offsprings will have thalassemia major b b, risk of having a child with thalassemia major is 0. 50 of the offspring b,b will be carriers like father. 