In the screenings of SCD genes, known gene mutations have been found in 20%–25% of the patients examined; 60% of SCD is caused by DLL3 mutations (Bonafe, Giunta, Gassner, Steinmann, & Superti‐Furga, 2003; Turnpenny et al., 2003; Turnpenny, Sloman, & Dunwoodie, 1993; Whittock et al., 2004). Here, DLL3 is linked to Schnyder corneal dystrophy.