Hi Kathy,
Many thalassemia minors report no symptoms, but from the hundreds of minors who have joined this group, we also have to conclude that many minors do have symptoms. The severity of the symptoms seems to be related to how low the long term hemoglobin level is. The long term effects of low hemoglobin and the resulting hypoxia (low oxygen) have never been studied, as most doctors and researchers have believed that there are no symptoms in thal minor. I feel that this is a direct result of doctors not compiling the information given to them by patients, and also just outright rejection of the idea that any symptoms a person may have are related to being a minor. We know that this thinking is not valid because so many minors have come to this group with very similar stories and sets of symptoms.
With that said and based on these many posts and talks with minors and an understanding of what to expect in more serious thalassemia conditions, I will say what I suspect the long term effects of thal minor are. First, thal minor does seem to have a positive effect on the heart in terms of protection against heart disease. This has been noted in studies, so not everything about it is a negative. However, long term oxygen deficiency can lead to pulmonary hypertension (PHT or PAH) which is high blood pressure in the artery between the heart and lungs. This is not related to your regular blood pressure. With the long term lack of oxygen comes a reduction in the amount of nitric oxide (NO) found in the artery and the heart. This causes a loss of flexibility of the artery and a reduction in its effectiveness in moving blood to the heart. PHT is common in non-transfused thalassemia intermedias and I suspect that mild PHT is common in thal minors, but this has never been studied. Even mild PHT can cause problems, so prevention should be a goal. The supplement, L-carnitine helps to fix NO in the body, so it is often recommended to thals and I think thal minors can also benefit from its use. I would also highly recommend natural vitamin E. Many minors report problems that are related to poor circulation, and again this may be a result of mild PHT, as the veins and arteries lose flexibility, thereby impairing circulation. I don't think liver damage is a concern unless you have had long periods of iron overload, which can happen with long term iron supplementation and excess iron absorption from the diet, with the latter being related to Hb level. The lower the Hb, the more likely that excess iron absorption from diet will occur.