Mannosidosis, alpha B, lysosomal

A lysosomal storage disease characterized by accumulation of unbranched oligosaccharide chains. This accumulation is expressed histologically as cytoplasmic vacuolation predominantly in the CNS and parenchymatous organs. Depending on the clinical findings at the age of onset, a severe infantile (type I) and a mild juvenile (type II) form of alpha-mannosidosis are recognized. There is considerable variation in the clinical expression with mental retardation, recurrent infections, impaired hearing and Hurler-like skeletal changes being the most consistent abnormalities.