STAG1 and neurodevelopmental disorder: Subsequent gene panels for disorders of sex development and neurodevelopmental disorders identified a pathogenic variant in STAG1: NM_005862.3:c.2116del p.(Asp706Ilefs*15)—a rare frameshift mutation in a highly conserved region of the gene, resulting in an early truncation of the protein [6]; Sanger sequencing performed for the trio (the child and both parents) proved its de novo status.