SOD2 and thanatophoric dysplasia: Thus, MnSOD Val-9Ala may play a particularly important role in the treatment of TD by EGb761 by affecting mitochondrial MnSOD concentrations Since patients with the Ala allele showed better improvement with EGb761 treatment in our current study, we speculate that these patients with the Ala allele may have greater MnSOD activity, which contributes to more free radical scavenging and stronger antioxidant effects of EGb761.