β-mannosidosis

β-man·no·si·do·sis (man″o-sĭ-doґsis) an autosomal recessive lysosomal storage disease caused by mutation in the MANBA gene (locus: 4q22-q25), which encodes β-mannosidase; the resulting enzyme defect leads to oligosaccharide accumulation. Manifestations, age of onset, and severity vary widely. Characteristics include mental retardation, motor and developmental delay, behavioral problems, hearing loss, speech impairment, seizures, hypotonia, peripheral neuropathy, angiokeratoma, skeletal abnormalities, mild facial dysmorphism, and recurrent infection.