These included Pierson syndrome (LAMB2 variants resulting in microphthalmia); MELAS and MIDD ( mitochondrial variants with inherited retinal degeneration); papillorenal syndrome (PAX2, with abnormal disc vasculature); and the Wilm’s tumour, Aniridia, genitourinary anomalies and impaired intellectual development (WAGR) syndrome (, WT1, with aniridia); Alport syndrome (COL4A3, COL4A4, COL4A5, with lenticonus and fleck retinopathies, temporal retinal thinning, maculopathy and macular hole); and Fabry disease (GLA, with corneal verticillata, and tortuous vessels) (Figs. 2, 3 and 4). Here, COL4A5 is linked to Alport syndrome.