Effect of vitamin D receptor (VDR) genotypes on the risk for osteoporosis in type 1 Gaucher disease

The almost universal finding of osteopenia in Gaucher disease and the unpredictable advent of avascular necrosis and/or pathological fractures are clinically relevant issues that are not necessarily reversed by specific enzyme replacement therapy (ERT). However, genetic/epigenetic factors may explain variance for bone mineral density (BMD) in the normal population. Among the candidate genes, vitamin D receptor (VDR) polymorphisms have been correlated with BMD at the lumbar spine (LS) and femoral neck (FN) and/or fracture risk in various populations. Helsinki Committee approval was received. DNA samples from 15 healthy individuals and 83 non-neuronopathic adult patients with recent BMD data at LS and FN were tested for VDR polymorphisms FokI, ApaI, TaqI, and BsmI. Chi-square, Fisher's exact, analysis of variance (ANOVA), Scheffe post hoc, and non-parametric Kruskal-Wallis ANOVA were applied as appropriate. P values <0.05 was considered statistically significant. There were no significant differences between patients and controls in frequency of any of polymorphic genotypes. The ApaI and BsmI genotypes were correlated with the N370S/N370S Gaucher genotype (p=0.029, and p=0.061, respectively). There was a correlation between the BsmI genotype and skeletal involvement (p=0.018) and a trend to significance with Z scores at LS (p=0.084). There was a statistically significant correlation between the Taq1 variants and BMD at the FN (p=0.030) with the TT variant associated with lower BMD. As in other populations, VDR polymorphic genotype may be an independently sorting modifier in the prediction of BMD and bone involvement in Gaucher disease.