Examples include lissencephaly due to LAMA2 and CTSD variants in family F270, inherited retinal degeneration due to ABCA4 and PCARE in family F1895, anterior segment dysgenesis due to PXDN and CYP1B1 variants in family F656, developmental and epileptic encephalopathy due to SZT2 and UGDH variants in family F8406, and polycystic kidneys due to HNF1B and PKD1 variants in family F6917 (Fig. 2g). The gene discussed is CTSD; the disease is developmental and epileptic encephalopathy.