SLC7A9 and urolithiasis: When comparing individuals with mutations in SLC3A1 versus SLC7A9, there were no differences in gender (p = 0.37), age of presentation (p = 0.07), age of clinical diagnosis (p = 0.12), presence of UTI (p = 0.45) or urolithiasis (p = 0.57), eGFR (p = 0.11), calcium (p = 0.22), or cystine excretion (p = 0.07) (Table 2).