APCDD1 and hypotrichosis simplex: Previous studies have reported many casual genes associated with heredity hypotrichosis simplex such as LSS, CDSN, and APCDD1 (Shimomura et al. 2010a; Pasternack et al. 2013; Peled et al. 2020), while other studies highlighted that CDH3 variants cause hypotrichosis simplex with juvenile macular dystrophy (HJMD; OMIM #601553) that is manifested later in life (Sprecher et al. 2001; Saeidian et al. 2019; Schauren et al. 2020; Ahmed et al. 2021).