Osteoporosis in beta-thalassemia major patients: role of COLIA1 gene G-T polymorphism

ABSTRACT

Growth impairment and osteoporosis are serious causes of morbidity in patients with beta-thalassemia major [beta-TM]. Desferoxamine [DFO] toxicity and iron overload have been proposed as the main underlying reasons. G-T polymorphism in regulatory region of COLIA1 gene has recently been associated with reduced bone mass and osteoporotic fractures in postmenopausal women. To detect the possible implication of COLIA1 gene polymorphism in pathogenesis of osteoporosis in beta-TM. Twenty five patients with beta-TM and 20 healthy controls were investigated for the G-T polymorphism of COLIA1 gene using restriction enzyme analysis. Bone mineral density [BMD], growth parameters, serum ferritin level and duration of chelation therapy were also assessed. We detected a heterozygous polymorphism of COLIA1 gene in 12% of beta-TM patients and 25% of the control group. Thalassemic patients had significant lower BMD than normal controls [p < 0.01]. Significant correlation was observed between low BMD and both duration of DFO intake and high ferritin level. Within the control group Subjects with G/T genotype had significantly lower femoral and lumber BMD than those with G/G genotype. In thalassemic patients No significant difference was found in BMD between the two COLIA 1 genotypes. We cannot detect evident role for COLIA1 gene polymorphism in the pathogenesis of osteoporosis in this group of beta-TM patients although this role has been detected in the control group. Further studies that include higher number of patients and more than one genetic polymorphism are needed in order to evaluate the role of genetic factors in the pathogenesis of osteoporosis in thalassemic patients