Hi Angie!
Well in my opinion, this is better referred as
"Thal. gone bad Characteristics" You see, if you keep up with the treatment, then there might be no such complications at all, even for Thal. Majors.
Well anyway, apart from the bone deformities that Andy has described so well in detail, you can also add the enlarged belly, delayed puberty and grayish skin-tone to the Thal. Characteristics. These are as a result of noncompliance with the Iron chelation therapy. Our body has no natural mechanisms to remove the excess iron that we get from blood transfusions. As a result, this excess iron starts getting deposited in different organs causing organ damage.
The Iron deposit in the endocrine glads can cause hormonal unbalance and result in various problems such a delayed puberty which is also one of the visible characteristics of Thal. along with other disorders of the endocrine such as Diabetes etc.
Excess Iron is mostly stored in the Spleen and the Liver which results in their enlargement and thus you get the enlarged belly of child that is also visible characteristic of Thal.
Similarly, a grayish skin complexion is also a visible characteristics of Thal. which is also a result of Iron overload and deposit in the skin. Sometimes, this is attributed to a malfunctioning pituitary gland that is malfunctioning due to Iron overload. Either way, the dark skin complexion is a result of Iron overload in Thals.
All these can be avoided if the child is treated properly i.e given transfutions at a proper time keeping the HB within the normal range and the Iron properly chelated.Well, these are the ones that I can think of right now. Maybe you can point out other that I have missed and I'll try to give an explanation of it's reason.
Take care, Peace!