An observational study in Nephrolithiasis, sponsored by Hospices Civils de Lyon. Not yet recruiting at 2 sites in France. Open to participants aged 2 Years to 90 Years. Per ClinicalTrials.gov, last updated 2025-12-02.
Sponsored by Hospices Civils de Lyon · Observational
Biallelic loss-of-function variants in CYP24A1 have been identified as a common genetic cause of autosomal recessive hypercalcemia (ARH, ORPHA 300547, 1 in 80,000 live births), characterized by low PTH (parathyroid hormone) levels, a high 25-OH D/24,25-(OH)₂D ratio, and susceptibility to vitamin D intoxication.
In humans, heterozygous pathogenic variants in CYP24A1 have been proposed both as responsible for an autosomal dominant disorder and as a risk factor for nephrolithiasis, but the rarity and heterogeneity of human data prevent a definitive answer to this crucial question.
Nephrolithiasis is a complex disease in which nutritional factors - particularly sodium and protein intake (leading to hypercalciuria) - play a key role. It also has a heritability of 50%, suggesting the involvement of many genetic susceptibility factors, as well as monogenic forms (mainly autosomal recessive, but also dominant or X-linked), which have been identified in 10-20% of patients.
The increasing prevalence of nephrolithiasis, affecting approximately 10% of the general population over a lifetime, has a significant financial impact on healthcare systems and imposes a major burden of morbidity, justifying further investigation into the genetic underpinnings of nephrolithiasis.
The goal of the HeteroCYP project is to improve understanding of the phenotypes associated with heterozygous, compound heterozygous, and homozygous variants of CYP24A1 by comparing clinical and biological outcomes in patients according to their mutation type
324 studies on the registry are indexed under Nephrolithiasis; 90 are open to participants now.
This study's planned enrollment of 45 is below the median of 100 across 57 observational studies indexed under Nephrolithiasis.
Browse Nephrolithiasis studies →Hospices Civils de Lyon is the lead sponsor of 1,866 studies on the registry; 448 are open to participants now.
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The study focuses on patients who are CYP24A1 heterozygous, CYP24A1 homozygous, or compound heterozygous.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Group 1: Heterozygous Patients
Group 2: Homozygous / Compound Heterozygous Patients
Exclusion Criteria:
Patients carriers of a heterozygous CYP2A1 mutation with or without symptoms: history of nephrocalcinosis or nephrolithiasis
Biological: Supplementary blood samples for PBMC analysis at V2
Patients carriers of homozygous, and compound heterozygous CYP2A1 mutation with or without symptoms: history of nephrocalcinosis or nephrolithiasis
Biological: Supplementary blood samples for PBMC analysis at V2
Supplementary blood (serum and plasma) and urines samples for bio collection at V3
Prevalence of nephrolithiasis in patients who are CYP24A1 heterozygous and homozygous (or compound heterozygous)
Prevalence of nephrolithiasis (based on imaging) in patients who are CYP24A1
Time frame: Visit 2 (at least 24 hours after baseline)
Start is estimated for Dec 2025; primary completion for Oct 2026, 10 months later.
Of 27 observational studies under Nephrolithiasis, half reached primary completion within 23 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 54. This study's planned 10 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Nov 2025. You cannot join it, but the record below documents what was studied.
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