The R324X mutation is the most recurrent BFLS patient-mutation occurring at exon 10 (C.1024 C > T), impairing the ePHD2 domain, whereby PHF6 is proposed to function as a truncated protein (Ahmed et al, 2021; Chao et al, 2010; Crawford et al, 2006; Gecz et al, 2006; Jahani-Asl et al, 2016; Lower et al, 2004, 2002; Todd et al, 2015). The gene discussed is PHF6; the disease is Borjeson-Forssman-Lehmann syndrome.