IMPDH1 and Leber congenital amaurosis: When examining the nine overlapping genes known to cause both LCA and RP (Crb1, Cr, Ift140, Impdh1, Lrat, Prph2, Rdh12, Rpe65, Rs1, Spata7, Tulp1), we found enrichment in the retinoid cycle in rods as the predominantly overrepresented pathway (Table 4), similar to what was found when examining all 22 genes known to cause LCA.