In order to understand the pathological mechanisms underlying fucosidosis, we generated a constitutive knockout mouse model by inserting the Escherichiacoli neomycin phosphotransferase I (nptI) gene into exon 1 of the Fuca1 gene that encodes lysosomal α-L-fucosidase (Fig. S1A). This evidence concerns the gene FUCA1 and fucosidosis.