For this purpose, we compared swimming velocity, rotarod performance, and open field behavior of (i) wild-type mice (FAAH+/+ ctrl), (ii) FAAH-knockout mice (FAAH−/− ctrl), (iii) MLD mice (FAAH+/+, MLD) and (iv) FAAH-deficient MLD mice (FAAH−/− MLD). This evidence concerns the gene FAAH and metachromatic leukodystrophy.