PTEN missense mutation that results in the substitution of histidine at position 93 with arginine affects the conserved WPD loop of the phosphatase domain of PTEN. PTEN H93R (His93Arg) mutant shows markedly decreased phosphoinositide phosphatase activity (Redfern et al. 2010). PTEN H93R substituion is implicated in autism spectrum disorders (Butler et al. 2005).