SLC7A9 and cystinuria: Furthermore, while research on cystinuria has primarily focused on clinical and genetic aspects to date, considering patient groups without SLC3A1/SLC7A9 mutations, it appears that additional studies are necessary, including research on the physicochemical factors related to cystine aggregation, similar to the results observed in calcium stone studies, and investigations into other urinary tract symptoms that may arise due to cystine crystal formation [34,35].