Searching for CYP24A1 mutations in cohorts of patients with calcium nephrolithiasis

IntroductionThe genetics underlying the idiopath-ic hypercalciuria leading to calcium-containing renal stones remains elus-ive. The discovery of rare monogenic tubulopathies, often leading to hype-rcalciuria, has increased our underst-anding of tubular physiology and pat-ho-physiology. However, insights int-o idiopathic calcium stone formation have not been gained from these dis-orders. The aim of this study is to ex-amine CYP24A1 mutations in cohorts of patients with calcium nephrolithi-asis.Materials and MethodsWe examined two cohorts of stone-forming patients for mutations in CYP24A1, which encodes the vitamin D24-hydroxylase enzyme. The first cohort had a biochemical phenotype of suppressed parathyroid hormone and high normal serum calcium, whilst the second cohort had a hypercalciuria phenotype. We did not identify bi-allelic sequence variants in CYP24A1 in our cohorts.ResultsIn cohort 1, we identified 9 known s-equence variants. In cohort 2 we ide-ntified 7 known sequence variants.ConclusionCYP24A1 mutations remain a rare cause of calcium nephrolithiasis and hypercalciuria.