A recent meta-analysis suggested that the absolute difference in number of repeats between cases and controls was <1 repeat, although the presence of shorter repeats seemed to be modestly associated with PCa risk.[67] Another meta-analysis showed that AR CAG repeat polymorphism with ≧20 repeats might confer a protective effect among the PCa patients with 45 years older but not all the patients with PCa.[68] However, these results remained unclear. This evidence concerns the gene AR and posterior cortical atrophy.