Peroxisome proliferator-activated receptor- γ (Pro12Ala polymorphism) and risk of osteopenia in β-thalassemia major patients

Abstract

Patients with beta thalassemia major (β-TM) frequently have bone disorders of multifactorial etiology. The main reason of the bone changes in β-TM is chronic expansion of red marrow leading to widening of the medullary space. Other possible factors which affect bones in β-TM patients are hypoparathyroidism , changes of vitamin D metabolism, deficiencies of calcitonin, osteocalcin, sex steroids, vitamin C and defective activity of growth hormone (GH) ∕ insulin –like growth factor – 1(IGF-1) ∕ insulin- like growth factor binding protein -3(IGFBP-3) and desferrioxamine (DFO) toxicity. It has been found that genetic factors influence the BMD level in patients with β-thalassemia, one of these factors is Peroxisome proliferator-activated receptor-γ (PPARγ) which plays an important role in osteogenesis , PPARγ is a subtype of the PPAR family that regulate lipid and glucose metabolism , the PPARγ gene is located on 3p25 in humans and is composed of nine exons , several nucleotide polymorphisms (SNPs) have been detected in the PPARγ gene in humans. One of these polymorphisms is Pro12Ala (rs1801282), which has the substitution of proline to alanine at codon 12 in exon B . The aim of this study was to to study the effect of the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-γ (PPARγ) gene on bone mineral density (BMD) ,using DEXA scan , and possible relation to osteopenia in β-thalassemia major (βTM) patients.