Thr300Ala ATG16L1 polymorphisms and bone strength in Crohn’s disease patients

Introduction: Studies on the effect of deletion of ATG5 and ATG7 proteins on bone cell function and bone strength in laboratory mice have revealed an association between autophagy and osteoporosis. The effect on bone strength of the Thr300Ala variant (rs2241880 polymorphism) of theATG16l1 gene, a Crohn’s diseasesusceptibility gene essential in macro- autophagy, has not yet been explored. Methods: 101 Crohn’s disease patientsunderwent DEXA bone density scanning. Real time PCR, high resolution melt (HRM) and restriction fragment length polymorphism (RFLP) were made use of as to assess for the rs2241880 polymorphism of the ATG16L1 gene in these patients. Results: HRM and RFLP demonstrated that 39.6% had the wild type rs2241880 (Thr300Ala) polymorphism while 7.9% were homozygous and 52.5% were heterozygous for the polymorphism. Mean DEXA bone mineral density scores in these patients showed lower T scores at the hip (- 1.74) among patients with the homozygous polymorphism than among patients with the heterozygous polymorphism (mean T score hip: -1.29). The highest mean T scores were found in patients with the wild type polymorphism (-1.04). Discussion: This study demonstrates the first evidence that polymorphisms in the ATG16L1 gene may play a role in bone metabolism.