I don't know what the actual rules say, but clearly with thalassaemia major you'd have no chance. Conceivably, with some varieties of thalassaemia minor a person could function as a professional pilot. However, I suspect that because crises can occur in thalassaemia minor (in the form of red blood cells bursting apart) when the person is subject to hypoxia, that many licencing authorities would say no.
My suggestions are:
1. Ask your own licencing authority.
2. Ask the Cyprus licencing authority what they do, since thalassaemia is endemic there.
QDM