Germline mutations in Phf6 causes the X-linked intellectual disability (XLID), Börjeson-Forssman-Lehmann syndrome (BFLS), characterized by impairments in cognitive function, epileptic-like seizures, and behavioural disturbances (Lower et al, 2002), in addition to endocrine defects (McRae et al, 2020). Here, PHF6 is linked to cask-related x-linked intellectual disability.