I think there is a mistake in the one lab report. Cap +1 (A-C) is a silent beta mutation and when combined with another thal minor can cause intermedia thal. Cd 15(G-A) is listed as a beta zero mutation.The Xmnl Polymorphism and the alpha mutation can both work as moderators of the condition, again leading to an intermedia state. Because of the complexities involved when moderator genes are present, I don't want to guess which report is correct, although I am leaning towards the Cap +1 (A-C) mutation, as it typically leads to intermedia when combined with another beta mutation. Cap +1 (A-C) would also be difficult to detect in the parent by electrophoresis, so even if both parents had gone through routine testing before getting pregnant, the mutation may not have been discovered until DNA analysis was done.
The child should also be taking folic acid. FYI, hydroxyurea has been shown to work better when other fetal hemoglobin producing supplements are taken along with it. Among these are wheatgrass, resveratrol, magnesium and L-carnitine.
Side effects of hydroxyurea are usually mild, often vanishing after the first few weeks, and do not persist once the drug is stopped. I will mention that better fetal hemoglobin inducing drugs are in development, so I don't perceive hydroxyurea being a lifelong obligation for patients today.
I know this is new and upsetting, but I want to reassure you that immense progress is being made in the treatment of thalassemia and that your daughter's prospects look good for the future. I have been involved with thalassemia for 10 years and in those 10 years, treatment has made great advances and the understanding of thal intermedia has grown substantially. The future is full of hope based on research going on today. I expect that thalassemia will be treated much differently in the coming years.