KANSL1 and Koolen-de Vries syndrome: Koolen-de Vries syndrome (ORPHA:96,169) is a RD characterized by visual impairments, cardiovascular defects, renal and urogenital anomalies, which have been individually highlighted in a cohort of 45 patients with either a 17q21.31 microdeletion encompassing the KAT8 regulatory NSL (non-specific lethal) complex subunit 1 gene or a truncating variant in the KANSL1 gene scattered throughout the gene (Koolen et al. 2016).