Aspartylglycosaminuria is an autosomal recessive disorder of glycoprotein catabolism, characterized by presence of aspartyglycosamine in the urine, progressive mental retardation, coarse face, impaired speech and motor functions, and signs of involvement of connective tissue and skeleton. In infancy, clinical symptoms are mild or absent. Vacuolized lymphocytes are often found in the blood and bone marrow. The disease appears unusually common in Finland.