Trigonocephaly was detected in 9/10 BOPS patients with a proven mutation in ASXL1 (Hoischen et al., 2011; Magini et al., 2012; Dangiolo et al., 2015) and in 28/30 patients not tested for this gene (Hastings et al., 2011). This evidence concerns the gene ASXL1 and Bohring-Opitz syndrome.