Hi Renee,
Hemoglobin H disease involves 3 of the 4 alpha hemoglobin genes. These genes are deleted or mutated, leaving only one functional alpha hemoglobin gene. A child receives two alpha genes from each parent, so if a child has HbH disease, both parents must carry at least one bad alpha gene. If the child had two good alpha genes, it is alpha thal trait. If your son has HbH he received at least one alpha thal gene from both parents. This is very relevant in terms of family medical history. It is almost impossible to determine alpha carrier state, so it is extremely important for future generations to be aware of this family history.
The severity of HbH varies greatly, with some patients needing transfusions. Certain environmental factors can cause a worsening of the condition and should be avoided. These include sulfa drugs, fava beans and moth balls. Infections should be treated quickly as alpha can worsen with infection. Adding anti oxidants like vitamin E and B complex may also be helpful. Because outside factors can be a factor on his health he should try to always take care of himself and never neglect seeing a doctor when he is sick.
Two very good clinical articles about alpha thalassemia can be found at
http://www.emedicine.com/med/topic2259.htmhttp://sickle.bwh.harvard.edu/thalover.htmlI have never seen a lot of information available on the long term experience of alpha thals. Those I have known have had widely varying health conditions. I think the main thing your son can do is stay as healthy as he can. Proper nutrition, supplements and regular exercise all play an important role. I do think his hemoglobin level should be checked at least annually, and if there is any noticeable change in Hb, he should probably have a complete blood count done. Recognizing that he has a serious health issue and dealing with this in terms of working towards good health and seeking medical care whenever needed, may have a large impact on his future health.