COL2A1 is a candidate PCa risk gene,35 and the HDAC5 histone deacetylase gene is frequently downregulated or deleted in PCa, resulting in increased H3K27 acetylation and impaired RB‐mediated repression of cell cycle‐related pro‐oncogenic genes.36 The gene discussed is COL2A1; the disease is posterior cortical atrophy.