The c.29T>C polymorphism of the transforming growth factor beta-1 (TGFB1) gene, bone mineral density and the occurrence of low-energy fractures in patients with inflammatory bowel disease.

Gastrointestinal tract conditions are frequently associated with low bone mineral density and increased risk of fractures due to osteoporosis, the latter concerning particularly inflammatory bowel disease (IBD) patients. One of the candidate genes involved in osteoporosis is the transforming growth factor beta-1 (TGFB1) whose polymorphisms may be responsible for the development of this disease. The aim of this study was to analyse the frequency of TGFB1 polymorphic variants and determine the association between the c.29T>C TGFB1 polymorphism, and bone mineral density and fractures in IBD patients. The study subjects included 198 IBD patients [100 suffering from Crohn's disease (CD) and 98 from ulcerative colitis (UC)] and 41 healthy volunteers as a control group. Densitometric bone measurements were obtained using dual energy X-ray absorptiometry. The TGFB1 genotyping was conducted using restriction fragments length polymorphism. We conducted an analysis of genotype distribution's concordance with Hardy-Weinberg equilibrium. We found statistically significant differences in lumbar spine (L2-L4) and femoral neck BMD and T-scores between CD, UC and control subgroups. The distribution of TGFB1 polymorphic variants among CD and UC patients was concordant with Hardy-Weinberg equilibrium. There were no statistically significant differences in densitometric parameters (lumbar spine and femoral neck BMD, T-score, and Z-score) between carriers of different TGFB1 polymorphisms among IBD (CD and UC) patients nor among controls. We have found no statistically significant differences in the prevalence of low-energy fractures between groups of different TGFB1 polymorphic variant carriers. The allele dose effect, recessive effect and dominant effect analysis did not show an association between low-energy fractures and the TGFB1 polymorphisms among CD and UC patients. We have not observed an association between the c.29T>C TGFB1 polymorphic variant and the bone mineral density within the cancellous and cortical bones (L2-L4 and femoral neck, respectively), or the occurrence of fractures among the IBD patients and their family members.

Bone mineral density and the 570A>T polymorphism of the bone morphogenetic protein 2 (BMP2) gene in patients with inflammatory bowel disease: a cross-sectional study.

Finding genetic predictors of osteoporosis and fractures in patients with inflammatory bowel disease (IBD) may provide incentives for non-pharmacological actions and so improve the long-term prognosis of the patients. We analysed the incidence of BMP2 570A>T polymorphic variants and their association with bone mineral density (BMD) and the incidence of fractures in patients with IBD. The study comprised 198 IBD patients (100 with Crohn's disease (CD), and 98 with ulcerative colitis, (UC)) and 41 healthy controls. Bone densitometric analysis was carried out using the DXA method. The 570A>T polymorphisms in the BMP2 gene were genotyped using RFLP. We found significant differences in the BMD and T-scores of the lumbar spine (L2-L4) and femoral neck between the three groups. In controls and CD patients, the highest L2-L4 BMD was found in carriers of the AA variant of the BMP2 gene, while among UC patients it was the case of TT carriers. In both femoral neck and lumbar spine among UC patients, the highest BMD was observed in carriers of the TT variant of the BMP2 gene. Among patients with CD and in the control group, the highest L2-L4 BMD was found in carriers of the AA variant, whereas in UC patients, it was the case of TT homozygotes. Within the femoral neck, there were no significant differences in BMD for the carriers of individual variants of BMP2 gene polymorphism. We conclude that the 570A>T polymorphism of the BMP2 gene, no statistically significant relationship was observed between the polymorphic variant and bone mineral density or the incidence of fractures in IBD patients.