What are familial and urinary infection risk factors for stones?

A- Familial factors: - We find a familial history in approximately 40% of cases. The cystinuria is the genetic disease mostly frequently found in this context. b- Urinary infection: - Certain germs, like proteus mirabilis, klebsielle and pseudomonas include the enzyme urease, which degrades the urea into a protein matrix upon which mineral salts precipitate in order to form phosphoammoniaco-magnesium stones. They mainly originate from coralliform stones= struvite