Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Pediatrics

Background: Osteoporosis is a prominent cause of morbidity in patients with thalassemia major (TM) with a complex pathophysiology. Osteoprotegerin (OPG) and receptor activator of NF-kappa-B ligand (RANKL) have been recently implicated in the pathogenesis of various types of osteoporosis. Aims: To characterize the possible role of the OPG and its gene polymorphisms in the pathogenesis of osteoporosis in thalassemia major, as well as their relationship with bone mineral density (BMD). Patients and methods: In 60 Egyptian thalassemic patients and 60 healthy control children (age = 5-14 year), serum OPG measured by ELIZA and OPG single nucleotide polymorphisms (SNPs) (rs2073618 and rs2073617) detected by PCR-RFLP technique.The patients had recent results of BMD scanning using dual X-ray absorptiometry (DEXA). Results: High prevalence of bone diseases was detected in TM patients, 40% had spine low bone mass, 10% had femur low bone mass, 70% complained from bone pain, 8.3% had history of long bone fracture related to minor trauma, and one patient had osteoporosis.The thalassemic patients showed significantly lower serum levels of OPG (P=0.003) and OPG/RANKL ratio (P= < 0.0001) as compared with controls. We couldn{u2019}t demonstrate significant association between serum OPG levels and BMD. Concerning OPG SNP rs2073618 we found that the G allele (P = 0.006) and GC genotype (p = 0.001) occurred more frequently in thalassemic patients with femur low bone mass than those with femur BMD Z- score > -2. While there was no relation between OPG SNP rs2073617 and BMD at any site of measurements

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