Recently, a growing role of SVs has been reported in Mendelian diseases with the improvement of methodology development for sequencing and data analysis (Alkan et al. 2011; Sanchis-Juan et al. 2018), mostly based on analysis of regulatory elements inside or close to a known functional gene, such as the duplications downstream of IRX1 for North Carolina macular dystrophy (Cipriani et al. 2017). Here, IRX1 is linked to hereditary disease.