Oligosaccharidoses

Oligosaccharidoses are a group of lysosomal diseases, also called glycoproteinoses, biochemically characterized by storage of protein-bound oligosaccharides within lysosomes and excretion with urine of corresponding sugars. Storage of oligosaccharides results from absence or defective function of a specific lysosomal enzyme. Classification includes α‎ and β‎ mannosidosis, fucosidosis, sialidosis types I and II, Schindler disease, and aspartylglycosaminuria. Galactosialidosis characterized by deficiency of β‎-galactosidase and α‎-neuraminidase with presence in patient urine of oligosaccharides has been included among oligosaccharidoses but may be better classified as a lysosomal enzyme protection defect disease in relation to its primary defect of cathepsine A-protective protein. The clinical spectrum of the diseases vary widely, as is common in lysosomal storage disorders. Patients frequently have neurological symptoms, but in rare cases presenting in adulthood symptoms may be very subtle. Psychiatric presentations have been described in adults. For adult cases, no treatments are available except for supportive care.