VDR and Familial adenomatous polyposis: In addition, the A/G SNP of the vitamin D metabolizing enzyme (CYP24A) was associated with increased risk of desmoid tumors compared to the control (Supplementary Table S3), suggesting that altered activity of the vitamin D/VDR pathway associated with polymorphisms in genes known to regulate vitamin D activity may be linked to the incidence of extracolonic lesions in FAP patients.