Q: I am a 28-year-old woman married for the past three years. We wish to have a baby now. I have thalassaemia minor. My husband got his Hb A2 test done and the result shows 1.6% of Hb A2 in his blood. Is it safe for us to go ahead and plan a baby? My brother is thalassaemia major and I have seen the pain and ordeal associated with his life.

A:The beta-thalassaemia syndromes (thalassaemia major and beta-thalassaemia intermedia) occur due to the absence of or a reduction in the synthesis of structurally normal beta-globin chains, the normal constituents of hemoglobin. This beta-globin chain deficiency leads to severe anemia by impairing the formation of functional Hb A (the normal Hb found in adults). The severity of these disorders is determined primarily by the type of the gene defect as well as the gene dosage. The normal Hb A2 level in an adult is less than 3.5% and it is elevated (>4%) in beta-thalassaemia trait. Beta thalassaemia trait (or heterozygous beta-thal or thal minor or thal carrier) is a clinically benign disorder. The importance lies in the fact that if both parents are carriers (i.e. carry one abnormal beta-gene), an offspring may co-inherit a beta-thalassaemia gene from both the parents making it homozygous resulting in a medically significant thalassaemia (beta-thalassaemia major). As your husband is normal (and I assume his complete blood count is normal), there is no problem. There are, however, very rare instances where a thal carrier may have normal Hb A2 level and such cases can be detected only by DNA analysis (so called Silent or near silent beta-thalassaemia trait).