Sialuria

Definition

A rare disorder of sialic acid metabolism characterized by excretion of large quantities of free sialic acid (predominantly N-acetylneuraminic acid without any morphologic evidence of storage within any subcellular organelle), mildly coarse facial features and hepatosplenomegaly. Growth and development are rather normal, however some affected individuals were reported to have moderate developmental delay, slight motor delay and mild intellectual impairment. Additional clinical features may involve macrocephaly, mild small airway obstruction, frequent upper respiratory tract infections, transient failure to thrive, seizures and sleep apnea. Signs and symptoms can be transient, especially in infancy.