PHF8 (KDM7B), as a histone demethylase, is responsible for demethylation of H3K9me1/2, H3K27me2 and H4K20me1, allowing transcription of downstream genes (Liu et al. 2010), and is involved in hepatocellular carcinoma (Ye et al. 2019), X-chromosome-linked intellectual disability (XLID) (Chen et al. 2018), melanoma (Moubarak et al. 2022), esophageal cancer (Sun et al. 2013) and so on. Here, PHF8 is linked to cask-related x-linked intellectual disability.