Gene (OMIM No.)
Function of gene/protein
  • Lysosomal alpha-mannosidase
  • Involved in the degradation of glycoproteins
Clinical phenotype
(OMIM phenotype no.)
  • Autosomal recessive
Ocular features
  • Corneal clouding
  • Retinal degeneration
Visual function
  • Progressive vision loss due to retinal and corneal involvement
Systemic features
  • Mental retardation
  • Skeletal abnormalities
  • Immunodeficiency
Key investigations
  • Enzyme assays: reduced alpha-mannosidase activity
  • Genetic testing: identification of MAN2B1 mutations
  • Enzyme replacement therapy
  • Supportive care and management of systemic symptoms
Therapies under research
  • Enzyme replacement therapy under investigation

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  1. Bell SJ, Oluonye N, Harding P, Moosajee M. Congenital cataract: A guide to genetic and clinical management. Therapeutic Advances in Rare Disease. 2020 Jul;1:2633004020938061.

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Updated on July 8, 2024
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