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Reduced leukocyte alpha-mannosidase activity

MedGen UID:
Concept ID:
HPO: HP:4000190


Concentration or activity of an alpha-mannosidase as measured in leukocytes is below the limits of normal. [from HPO]

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVReduced leukocyte alpha-mannosidase activity

Conditions with this feature

Deficiency of alpha-mannosidase
MedGen UID:
Concept ID:
Disease or Syndrome
Alpha-mannosidosis encompasses a continuum of clinical findings from mild to severe. Three major clinical subtypes have been suggested: A mild form recognized after age ten years with absence of skeletal abnormalities, myopathy, and slow progression (type 1). A moderate form recognized before age ten years with presence of skeletal abnormalities, myopathy, and slow progression (type 2). A severe form manifested as prenatal loss or early death from progressive central nervous system involvement or infection (type 3). Individuals with a milder phenotype have mild-to-moderate intellectual disability, impaired hearing, characteristic coarse features, clinical or radiographic skeletal abnormalities, immunodeficiency, and primary central nervous system disease – mainly cerebellar involvement causing ataxia. Periods of psychiatric symptoms are common. Associated medical problems can include corneal opacities, hepatosplenomegaly, aseptic destructive arthritis, and metabolic myopathy. Alpha-mannosidosis is insidiously progressive; some individuals may live into the sixth decade.

Professional guidelines


Gruner S, Diezel W, Zwirner A, Müller GM, Von Baehr R, Sönnichsen N
Br J Dermatol 1987 Jun;116(6):785-92. doi: 10.1111/j.1365-2133.1987.tb04896.x. PMID: 3040068

Recent clinical studies


Erlichman N, Meshel T, Baram T, Abu Raiya A, Horvitz T, Ben-Yaakov H, Ben-Baruch A
Cells 2023 Sep 23;12(19) doi: 10.3390/cells12192338. PMID: 37830552Free PMC Article


Bennet JK, Dembure PP, Elsas LJ
Am J Med Genet 1995 Jan 2;55(1):21-6. doi: 10.1002/ajmg.1320550108. PMID: 7702090
Prence EM, Natowicz MR
Clin Chem 1992 Apr;38(4):501-3. PMID: 1568314
Steadman R, Petersen MM, Topley N, Williams D, Matthews N, Spur B, Williams JD
J Immunol 1990 Apr 1;144(7):2712-8. PMID: 2156933

Clinical prediction guides

Xiang ZG, Jiang DD, Liu Y, Zhang LF, Zhu LP
Transgenic Res 2010 Feb;19(1):67-75. Epub 2009 Jul 2 doi: 10.1007/s11248-009-9299-3. PMID: 19572206
Morgan R, Gao G, Pawling J, Dennis JW, Demetriou M, Li B
J Immunol 2004 Dec 15;173(12):7200-8. doi: 10.4049/jimmunol.173.12.7200. PMID: 15585841
Cooper A, Hatton C, Thornley M, Sardharwalla IB
J Inherit Metab Dis 1988;11(1):17-29. doi: 10.1007/BF01800054. PMID: 3128685

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