lysosomal alpha-mannosidosisA lysosomal storage disease (OMIM:248500) characterised by accumulation of unbranched oligosaccharides, which causes cytoplasmic vacuolation in the CNS and solid organs. It presents in two types:
• Type 1—Severe infantile form.
• Type 2—Mild juvenile form.
Variable mental retardation, recurrent infections, impaired hearing, Hurler-like skeletal changes.
Defects of MAN2B1, which encodes an enzyme required for catabolising N-linked carbohydrates released during glycoprotein turnover, cause lysosomal alpha-mannosidosis.