Although there are no studies in the literature linking the PBX1 gene to nephrolithiasis, we postulate that this SNP in the PBX1 gene may change the expression or the interaction of this gene with others during kidney development and that this may alter the renal absorption capacity of cystine and other amino acids, increasing the possibility of cystinuria development. The gene discussed is PBX1; the disease is cystinuria.