In a study of 100 healthy girls, R. Chowdhary et al. found that the homozygous polymorphic VDR allele was associated with severe secondary hyperparathyroidism and hypovitaminosis D, with a prevalence of 84.9% to 100% — similar to the prevalence of 70.3% to 100% found in this study [47]. This evidence concerns the gene VDR and rickets.