Growth hormone secretion and bone histomorphometric study in thalassaemic patients with acquired skeletal dysplasia secondary to desferrioxamine.

An auxological and endocrinological study was performed in 21 thalassaemic patients with growth retardation and skeletal dysplasia secondary to desferrioxamine. Bone metaphyseal proximal tibial or iliac crest biopsy was performed in six patients with severe genu valgum or non-traumatic vertebral compression. GH insufficiency/deficiency (GH deficiency: peak after stimulation test below 6 ng/ml) was found in 72% of our thalassaemic patients with skeletal dysplasia, but in only 41% of patients without skeletal dysplasia. Bone histology showed abnormal chondrocytes, alteration of staining pattern of cartilage, irregular columnar cartilage and lacunae in the cartilaginous tissue. The behaviour of bone tissue was unpredictable (presence of thick or thin osteoid layer). Bone microfractures were sometimes present. The bone microstructure showed scarce mineralization, which was evenly or irregularly distributed. The bone tissue apatitic phase was quantitatively reduced. The hardness of bone tissue was remarkably lower than that of normal bone in three out of six patients. In conclusion, iron chelation therapy in patients with acquired skeletal dysplasia seems to interfere with GH secretion. The early identification of clinical and radiological abnormalities of skeletal dysplasia is of paramount importance in preventing severe bone destruction.