In a study published in 2005 by Bid et al. from Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, the association of vitamin D receptor-gene (Fok1) polymorphism with calcium oxalate nephrolithiasis was studied in 138 patients of calcium oxalates stones and 166 healthy patients. The gene discussed is VDR; the disease is nephrolithiasis, calcium oxalate.