FUCA1 is a lysosomal enzyme involved in the degradation of fucose-containing glycoproteins and glycolipids. Mutations in FUCA1 gene are associated with fucosidosis (FUCA1D), which is an autosomal recessive lysosomal storage disease. Different phenotypes include clinical features such as neurologic deterioration, growth retardation, visceromegaly, and seizures in a severe early form; coarse facial features, angiokeratoma corporis diffusum, spasticity and delayed psychomotor development in a longer surviving form; and an unusual spondylometaphyseoepiphyseal dysplasia in yet another form.