Table 5. Two candidate modifier loci are associated with disease severity in the cohort.

Gene:	RPGRIP1				RPGRIP1L				CEP290		IQCB1
cSNP:	P96Q	K192E	A547S	E1033Q	A229T	R744Q	G1025S	D1264N	K838E	L906W	I393N	C434Y
P value all	0.6224	0.3666	0.6835	0.2943	0.5637	0.0493	0.5227	0.9196	0.6984	NA	0.0438	0.9774
P value protein	0.0768	0.3721	0.2230	0.3018	0.5637	0.2444	0.2383	0.2677	0.3483	NA	1.0000	0.4239
P value null	0.0782	0.0834	0.1195	0.0770	NA	0.4551	0.7288	0.2572	0.1883	NA	0.0298	0.4870
P value ex 1–14	0.0707	0.0358	0.2658	0.0455	0.3173	0.3046	0.6687	0.5909	0.3046	NA	0.0176	0.2353
P value ORF15	0.0768	0.1706	0.0737	0.2528	1.0000	0.2444	0.6749	0.5318	0.3483	NA	1.0000	0.2296

Common coding SNPs in candidate modifier genes were tested for association with disease severity in the total cohort (“all” in left column) and in the subgroups with predicted translated RPGR protein (“protein” in left column), with predicted null alleles (“null” in left column), with exon 1–14 mutations (“ex 1–14” in left column), and with ORF15 mutations (“ORF15” in left column). P-values<0.05 are shown in bold.