Q: I need to know that if I am (38 years old) suspected to have thalassaemia, then can my sons (7 years and 8 months old) be affected by this disease? If so, what should I do?

A:Thalassaemia are a group of genetic diseases caused by the production of abnormal haemoglobin, the red coloured protein present in red blood cells that transports oxygen in the body. Haemoglobin comprises two beta (b)-globin and two alpha (a)-globin chains, their production being governed by 2b and 4a genes respectively. In b-thalassaemia, the production of b-chain is abnormal while in a-thal it is the a-chain. When only one beta-globin gene is affected (thal minor or trait or carrier), it results in mild anaemia not requiring treatment but the involvement of both genes results in severe disease (thalassaemia major or intermedia) requiring regular treatment and follow-up from infancy. The severe anaemia is due to impaired 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 b-thalassaemia trait. Beta thalassaemia trait (or heterozygous b-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 b-gene), an offspring may co-inherit a b-thalassaemia gene from both the parents making it homozygous resulting in a medically significant thalassaemia (b-thalassaemia major). Had your children been thalassaemics, they would have manifested by this age. You can get their Hb A2 and Hb F estimated to exclude the possibility of thal trait in them. 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 b-thalassaemia trait).