α-mannosidosis

α-man·no·si·do·sis (man″o-sĭ-doґsis) an autosomal recessive lysosomal storage disease caused by mutation in the MAN2B1 gene (locus: 19cen-q12), which encodes lysosomal α-mannosidase; the resulting enzyme defect leads to oligosaccharide accumulation. Characteristics include coarse facies, upper respiratory congestion and infections, profound mental retardation, hepatosplenomegaly, cataracts, radiographic signs of dysostosis multiplex, and kyphosis. There are two types: a severe type I (infantile onset), with death occurring between the ages of 3 and 10 years, and a milder type II (juvenile-adult onset).