First, Co‐IP experiments showed that PTBP1 interacted with RALY; Second, both PTBP1 and RALY could bind to the pre‐mRNA of DNMT3B and induced DNMT3B splicing switch from DNMT3B‐S to DNMT3B‐L in PCa cells; Third, RALY knockdown obviously reduced the binding abundance between PTBP1 and pre‐mRNA of DNMT3B. The gene discussed is RALY; the disease is posterior cortical atrophy.