Vol 10, Issue 10, 2017 Online - 2455-3891 Print - 0974-2441 POLYMORPHISM OF METHYLENETETRAHYDROFOLATE REDUCTASE (A1298C) AS A RISK FACTOR FOR OSTEOPOROSIS IN POST-MENOPAUSAL INDONESIAN WOMEN ELZA IBRAHIM AUERKARI 1,2 *, LINDAWATI KUSDHANY 2,3 , SRI SOFIATI UMAMI 4 , TRI BUDI WAHYUNI RAHARDJO 2,3 , CHRISTOPHER TALBOT 5 1 Department of Oral Biology, Faculty of Dentistry, University of Indonesia, Jakarta, Indonesia. 2 Centre for Ageing Studies, University of Indonesia, Depok, Indonesia. 3 Department of Prosthodontics, Faculty of Dentistry, University of Indonesia, Jakarta, Indonesia. 4 Department of Medical Biology, Faculty of Medicine, University of Indonesia, Jakarta, Indonesia. 5 Department of Genetics, University of Leicester, Leicester, UK. Email: eauerkari@yahoo.com Received: 26 May 2017, Revised and Accepted: 20 June 2017 ABSTRACT Objective: The study aimed to assess the association between the A1298C polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene and risk to osteoporosis in post-menopausal Indonesian women. Methods: After ethical approval, calcaneus bone mineral density (BMD) (T-scoring) was assessed from 194 consenting post-menopausal Indonesian women by dual-energy X-ray absorptiometry, and DNA of the participants was isolated from peripheral blood samples. To determine the status of A1298C polymorphism of MTHFR, isolated DNA was polymerase chain reaction (PCR) amplified in 35 cycles, to result in PCR product sizes of 302 bp (1298A) and 275 bp (1298C). For fragment detection, the PCR product was subjected to electrophoresis on agarose gel. The results were statistically assessed for genotype and allotype comparison according to the T-score grouping by Chi-square analysis, assuming statistical significance at p<0.05. Results: The results show no significant association between the T-score (BMD) grouping and genotype (or allotype) of the tested polymorphism of MTHFR. The observed genotype distribution of the tested MTHFR polymorphism (A1298C) differs clearly from those previously reported, with AC as the dominant genotype in the Indonesian sample population of the present work. Conclusion: The MTHFR (A1298C) polymorphism is relatively infrequent in the Indonesian female population, and no significant association was observed between this polymorphism, bone mineral density, and osteoporotic status. Keywords: Menopause, Osteoporosis, Methylenetetrahydrofolate reductase, Polymorphism, Bone mineral density. INTRODUCTION Permanently reduced or lost post-menopausal ovarian activity and provision of the estrogen hormone will lead in the long run to faster rate of bone resorption than formation and thereby increasing risk to osteoporosis [1,2]. This metabolic bone disease is marked by reduced bone mineral density (BMD) and increasing microstructural deterioration and fragility of the bone. The incidence of osteoporosis increases with age and time after menopause and at a typical level of about 15-40% is a major hazard for aging post-menopausal women practically everywhere in the world [3-5]. While both environmental and inherited factors affect bone strength, twin and family studies suggest that genetic factors account for more than half of the variance in BMD [5]. The variation implies corresponding shifts in the network of regulatory genes that are involved in the balance between the osteoblastic bone formation and osteoclastic bone resorption and associated pathological conditions. The methylenetetrahydrofolate reductase (MTHFR) gene localized at 1p36.3 encodes for an enzyme that catalyzes the irreversible reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a substrate for homocysteine remethylation to methionine. The involvement in homocysteine metabolism is thought to explain the adverse health impact of reduced enzyme activity by MTHFR polymorphisms [6]. The plasma homocysteine levels are affected by menopause, and for example, the C677T (rs1801133) polymorphism of MTHFR has been associated with increased skeletal fracture risk in post- menopausal women although not without some controversy [6,7]. It is therefore conceivable that other polymorphisms of this gene may carry an impact on the post-menopausal bone health. In particular, the other relatively common polymorphism A1298C (rs1801131) of MTHFR is known to result in the replacement of Glu-429 by alanine, reduced MTHFR activity but no or only mild hyperhomocysteinemia [8,9]. The present work aims to clarify the relationship of A1298C polymorphism of MTHFR in post-menopausal Indonesian women and their risk to develop osteoporosis. METHODS In total, 194 consenting post-menopausal Indonesian women were included in the study. T-scoring by dual-energy X-ray absorptiometry (DXA) was used to characterize the calcaneus bone mineral density (BMD) of the participants. A T-score <−2.5 was taken to indicate osteoporosis, −2.5≤ T-score <−1 osteopenia, and T-score ≥−1 normal (healthy) level of BMD. With these criteria, 72 (69 after dropouts during the genetic study) participants were included into the osteoporosis group, 59 (58) into the osteopenia group, and 63 (60) into the group of normal (healthy) participants. The study and applied methods were approved by the Ethical Committee of the University of Indonesia. For DNA isolation, 3 mL of peripheral blood was collected from each participant and inserted into a tube (15 mL) containing red blood cell lysis solution (1.45 M NH4Cl, 5 mM anhydrous EDTA, and 0.1 M KHCO 3 ). The tube was repeatedly inverted and then incubated © 2017 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4. 0/) DOI: http://dx.doi.org/10.22159/ajpcr.2017.v10i10.20272 Research Article