Three SNPs located in MTHFR, CTLA4, and XRCC1, in non-smoking UBCa patients and four SNPs located in HTRB1, Lig4, Serpin1, TGFb, and XRCC1 in non-smoking LCa patients (Table 5). The gene discussed is XRCC1; the disease is Leber congenital amaurosis.