Compared to two unrelated controls without aniridia (Fig. 3), both patients showed a significant reduction in normalized expression of PAX6 using RPLP0 as housekeeping gene (ANI-1, fold-change (FC) = 0.017; Dunn's test: adjusted p-value = 1.560E-05; ANI-2, FC = 0.073; p = 1.49E-06), and also a slight statistically non-significant reduction to those observed in two other patients from our cohort carrying disease-causing variants affecting PAX6 splicing (Additional file 1: Table S3). Here, RPLP0 is linked to isolated aniridia.