An autosomal recessive lysosomal storage disease caused by a deficiency of ALPHA-L-FUCOSIDASE activity resulting in an accumulation of fucose containing SPHINGOLIPIDS; GLYCOPROTEINS, and mucopolysaccharides (GLYCOSAMINOGLYCANS) in lysosomes. The infantile form (type I) features psychomotor deterioration, MUSCLE SPASTICITY, coarse facial features, growth retardation, skeletal abnormalities, visceromegaly, SEIZURES, recurrent infections, and MACROGLOSSIA, with death occurring in the first decade of life. Juvenile fucosidosis (type II) is the more common variant and features a slowly progressive decline in neurologic function and angiokeratoma corporis diffusum. Type II survival may be through the fourth decade of life. (From Menkes, Textbook of Child Neurology, 5th ed, p87; Am J Med Genet 1991 Jan;38(1):111-31) X