Such loss‐of‐function effect of PJA1 p.R376C variant in patients with NDD/trigonocephaly would be consistent to the previous observations of craniosynostosis in patients with 5q‐partial trisomy spanning MSX246, 47 and in transgenic mice overexpressing MSX248 in that increases of MSX2 protein could contribute to their pathological phenotypes. This evidence concerns the gene PJA1 and craniosynostosis.