Several studies have shown that multiple factors may act in concert to produce bone disease in TM including bone marrow expansion (5), hypogonadism (6,7,8), defective growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis (9,10,11,12), altered pattern of cytokines (13), iron deposit in bone (5,14,15), deferoxamine bone toxicity (16,17) and vitamin D deficiency (18). This evidence concerns the gene GH1 and vitamin D deficiency.