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Deficiency of alpha-mannosidase(MANSA)

MedGen UID:
7467
Concept ID:
C0024748
Disease or Syndrome
Synonyms: Alpha mannosidase B deficiency; Alpha-Mannosidosis; Lysosomal alpha-D-mannosidase deficiency; Mannosidosis, alpha B lysosomal; MANSA
SNOMED CT: alpha-Mannosidase deficiency (65524005); Alpha-D-mannosidosis (65524005); Alpha-mannosidase deficiency (65524005); Deficiency of alpha-mannosidase (124466001)
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
 
Gene (location): MAN2B1 (19p13.13)
 
Monarch Initiative: MONDO:0009561
OMIM®: 248500
Orphanet: ORPHA61

Disease characteristics

Excerpted from the GeneReview: Alpha-Mannosidosis
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. [from GeneReviews]
Authors:
Dag Malm  |  Øivind Nilssen   view full author information

Additional descriptions

From OMIM
Alpha-mannosidosis is an autosomal recessive lysosomal storage disease characterized by mental retardation, coarse facial features, skeletal abnormalities, hearing impairment, neurologic motor problems, and immune deficiency. Expression of the disease varies considerably, and there is a wide spectrum of clinical findings and severity. Affected children are often normal at birth and during early development. They present in early childhood with delayed psychomotor development, delayed speech, and hearing loss. Additional features include large head with prominent forehead, rounded eyebrows, flattened nasal bridge, macroglossia, widely spaced teeth, dysostosis multiplex, and motor impairment (summary by Malm and Nilssen, 2008). Classification Systems Two classification systems have been used to describe the clinical presentation of alpha-mannosidosis. The earlier system delineated a more severe 'type I,' which shows infantile onset, rapid mental deterioration, hypotonia, splenomegaly, severe dysostosis multiplex, and severe recurrent infections, often resulting in death by age 8 years. Individuals with the less severe 'type II' show normal early development with later childhood development of mental retardation, hearing loss, coarse facies, neurologic deterioration, and survival well into adulthood (summary by Desnick et al., 1976 and Gotoda et al., 1998). A later classification system delineated 3 clinical types. Type 1 is the mildest form, with onset after age 10 years, without skeletal abnormalities and very slow progression. Type 2 is a moderate form, with onset before age 10 years, presence of skeletal abnormalities, and slow progression with development of ataxia by age 20 to 30 years. Type 3 is the severe form, with onset in early infancy, skeletal abnormalities, and obvious progression leading to early death from primary central nervous system involvement or myopathy. Most patients belong to clinical type 2 (summary by Malm and Nilssen, 2008). Despite the clinical heterogeneity of the disorder, there are no apparent genotype/phenotype correlations (Berg et al., 1999; Riise Stensland et al., 2012).  http://www.omim.org/entry/248500
From MedlinePlus Genetics
Alpha-mannosidosis is a rare inherited disorder that causes problems in many organs and tissues of the body. Affected individuals may have intellectual disability, distinctive facial features, and skeletal abnormalities. Characteristic facial features can include a large head, prominent forehead, low hairline, rounded eyebrows, large ears, flattened bridge of the nose, protruding jaw, widely spaced teeth, overgrown gums, and large tongue. The skeletal abnormalities that can occur in this disorder include reduced bone density (osteopenia), thickening of the bones at the top of the skull (calvaria), deformations of the bones in the spine (vertebrae), knock knees, and deterioration of the bones and joints.

Affected individuals may also experience difficulty in coordinating movements (ataxia); muscle weakness (myopathy); delay in developing motor skills such as sitting and walking; speech impairments; increased risk of infections; enlargement of the liver and spleen (hepatosplenomegaly); a buildup of fluid in the brain (hydrocephalus); hearing loss; and a clouding of the lens of the eye (cataract). Some people with alpha-mannosidosis experience psychiatric symptoms such as depression, anxiety, or hallucinations; episodes of psychiatric disturbance may be triggered by stressors such as having undergone surgery, emotional upset, or changes in routine.

The signs and symptoms of alpha-mannosidosis can range from mild to severe. The disorder may appear in infancy with rapid progression and severe neurological deterioration. Individuals with this early-onset form of alpha-mannosidosis often do not survive past childhood. In the most severe cases, an affected fetus may die before birth. Other individuals with alpha-mannosidosis experience milder signs and symptoms that appear later and progress more slowly. People with later-onset alpha-mannosidosis may survive into their fifties. The mildest cases may be detected only through laboratory testing and result in few if any symptoms.  https://medlineplus.gov/genetics/condition/alpha-mannosidosis

Clinical features

From HPO
Growth delay
MedGen UID:
99124
Concept ID:
C0456070
Pathologic Function
A deficiency or slowing down of growth pre- and postnatally.
Hepatomegaly
MedGen UID:
42428
Concept ID:
C0019209
Finding
Abnormally increased size of the liver.
Sensorineural hearing loss disorder
MedGen UID:
9164
Concept ID:
C0018784
Disease or Syndrome
A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve.
Macrotia
MedGen UID:
488785
Concept ID:
C0152421
Congenital Abnormality
Median longitudinal ear length greater than two standard deviations above the mean and median ear width greater than two standard deviations above the mean (objective); or, apparent increase in length and width of the pinna (subjective).
Dysarthria
MedGen UID:
8510
Concept ID:
C0013362
Mental or Behavioral Dysfunction
Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.
Gliosis
MedGen UID:
4899
Concept ID:
C0017639
Pathologic Function
Gliosis is the focal proliferation of glial cells in the central nervous system.
Spasticity
MedGen UID:
7753
Concept ID:
C0026838
Sign or Symptom
A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.
Babinski sign
MedGen UID:
19708
Concept ID:
C0034935
Finding
Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract.
Hyperreflexia
MedGen UID:
57738
Concept ID:
C0151889
Finding
Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.
Abnormal pyramidal sign
MedGen UID:
68582
Concept ID:
C0234132
Sign or Symptom
Functional neurological abnormalities related to dysfunction of the pyramidal tract.
Corpus callosum atrophy
MedGen UID:
96560
Concept ID:
C0431370
Finding
The presence of atrophy (wasting) of the corpus callosum.
Global developmental delay
MedGen UID:
107838
Concept ID:
C0557874
Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Cerebellar atrophy
MedGen UID:
196624
Concept ID:
C0740279
Disease or Syndrome
Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event.
Limb ataxia
MedGen UID:
196692
Concept ID:
C0750937
Finding
A kind of ataxia that affects movements of the extremities.
Gait ataxia
MedGen UID:
155642
Concept ID:
C0751837
Sign or Symptom
A type of ataxia characterized by the impairment of the ability to coordinate the movements required for normal walking. Gait ataxia is characteirzed by a wide-based staggering gait with a tendency to fall.
Delayed myelination
MedGen UID:
224820
Concept ID:
C1277241
Finding
Delayed myelination.
Intellectual disability
MedGen UID:
811461
Concept ID:
C3714756
Mental or Behavioral Dysfunction
Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.
Spinocerebellar tract disease in lower limbs
MedGen UID:
870473
Concept ID:
C4024919
Disease or Syndrome
Cerebral cortical atrophy
MedGen UID:
1646740
Concept ID:
C4551583
Disease or Syndrome
Atrophy of the cortex of the cerebrum.
Inguinal hernia
MedGen UID:
6817
Concept ID:
C0019294
Finding
Protrusion of the contents of the abdominal cavity through the inguinal canal.
Hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.
Spondylolisthesis
MedGen UID:
52470
Concept ID:
C0038016
Disease or Syndrome
Spondylolisthesis is defined as forward slipping of a vertebral body on the one below it. Spondylolysis is defined as a defect in the pars interarticularis without vertebral slipping (summary by Wiltse et al., 1975).
Hurler syndrome
MedGen UID:
39698
Concept ID:
C0086795
Disease or Syndrome
Mucopolysaccharidosis type I (MPS I) is a progressive multisystem disorder with features ranging over a continuum of severity. While affected individuals have traditionally been classified as having one of three MPS I syndromes (Hurler syndrome, Hurler-Scheie syndrome, or Scheie syndrome), no easily measurable biochemical differences have been identified and the clinical findings overlap. Affected individuals are best described as having either a phenotype consistent with either severe (Hurler syndrome) or attenuated MPS I, a distinction that influences therapeutic options. Severe MPS I. Infants appear normal at birth. Typical early manifestations are nonspecific (e.g., umbilical or inguinal hernia, frequent upper respiratory tract infections before age 1 year). Coarsening of the facial features may not become apparent until after age one year. Gibbus deformity of the lower spine is common and often noted within the first year. Progressive skeletal dysplasia (dysostosis multiplex) involving all bones is universal, as is progressive arthropathy involving most joints. By age three years, linear growth decreases. Intellectual disability is progressive and profound but may not be readily apparent in the first year of life. Progressive cardiorespiratory involvement, hearing loss, and corneal clouding are common. Without treatment, death (typically from cardiorespiratory failure) usually occurs within the first ten years of life. Attenuated MPS I. Clinical onset is usually between ages three and ten years. The severity and rate of disease progression range from serious life-threatening complications leading to death in the second to third decade, to a normal life span complicated by significant disability from progressive joint manifestations and cardiorespiratory disease. While some individuals have no neurologic involvement and psychomotor development may be normal in early childhood, learning disabilities and psychiatric manifestations can be present later in life. Hearing loss, cardiac valvular disease, respiratory involvement, and corneal clouding are common.
Pectus carinatum
MedGen UID:
57643
Concept ID:
C0158731
Finding
A deformity of the chest caused by overgrowth of the ribs and characterized by protrusion of the sternum.
Frontal bossing
MedGen UID:
67453
Concept ID:
C0221354
Congenital Abnormality
Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline.
Flat occiput
MedGen UID:
332439
Concept ID:
C1837402
Finding
Reduced convexity of the occiput (posterior part of skull).
Enlarged cisterna magna
MedGen UID:
344031
Concept ID:
C1853377
Finding
Increase in size of the cisterna magna, one of three principal openings in the subarachnoid space between the arachnoid and pia mater, located between the cerebellum and the dorsal surface of the medulla oblongata.
Thoracolumbar kyphosis
MedGen UID:
383679
Concept ID:
C1855418
Anatomical Abnormality
Hyperconvexity of the thoracolumbar spine producing a rounded or humped appearance.
Malar flattening
MedGen UID:
347616
Concept ID:
C1858085
Finding
Underdevelopment of the malar prominence of the jugal bone (zygomatic bone in mammals), appreciated in profile, frontal view, and/or by palpation.
Generalized hypotonia
MedGen UID:
346841
Concept ID:
C1858120
Finding
Generalized muscular hypotonia (abnormally low muscle tone).
Thickened calvaria
MedGen UID:
346823
Concept ID:
C1858452
Finding
The presence of an abnormally thick calvaria.
Femoral bowing
MedGen UID:
347888
Concept ID:
C1859461
Finding
Bowing (abnormal curvature) of the femur.
Increased vertebral height
MedGen UID:
400628
Concept ID:
C1864853
Finding
Increased top to bottom height of vertebral bodies.
Macrocephaly
MedGen UID:
745757
Concept ID:
C2243051
Finding
Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium.
Abnormal rib cage morphology
MedGen UID:
871275
Concept ID:
C4025763
Anatomical Abnormality
A morphological anomaly of the rib cage.
Splenomegaly
MedGen UID:
52469
Concept ID:
C0038002
Finding
Abnormal increased size of the spleen.
Vacuolated lymphocytes
MedGen UID:
332307
Concept ID:
C1836855
Finding
The presence of clear, sharply defined vacuoles in the lymphocyte cytoplasm.
Recurrent bacterial infections
MedGen UID:
334943
Concept ID:
C1844383
Finding
Increased susceptibility to bacterial infections, as manifested by recurrent episodes of bacterial infection.
Decreased circulating antibody level
MedGen UID:
892481
Concept ID:
C4048270
Finding
An abnormally decreased level of immunoglobulin in blood.
Decreased circulating alpha-mannosidase activity
MedGen UID:
1841885
Concept ID:
C5826604
Finding
Concentration or activity of alpha mannosidase below the lower limit of normal in the blood circulation.
Reduced leukocyte alpha-mannosidase activity
MedGen UID:
1050558
Concept ID:
CN375661
Finding
Concentration or activity of an alpha-mannosidase as measured in leukocytes is below the limits of normal.
Macroglossia
MedGen UID:
44236
Concept ID:
C0024421
Disease or Syndrome
Increased length and width of the tongue.
Gingival overgrowth
MedGen UID:
87712
Concept ID:
C0376480
Finding
Hyperplasia of the gingiva (that is, a thickening of the soft tissue overlying the alveolar ridge. The degree of thickening ranges from involvement of the interdental papillae alone to gingival overgrowth covering the entire tooth crown.
Mandibular prognathia
MedGen UID:
98316
Concept ID:
C0399526
Finding
Abnormal prominence of the chin related to increased length of the mandible.
Epicanthus
MedGen UID:
151862
Concept ID:
C0678230
Congenital Abnormality
Epicanthus is a condition in which a fold of skin stretches from the upper to the lower eyelid, partially covering the inner canthus. Usher (1935) noted that epicanthus is a normal finding in the fetus of all races. Epicanthus also occurs in association with hereditary ptosis (110100).
Low anterior hairline
MedGen UID:
331280
Concept ID:
C1842366
Finding
Distance between the hairline (trichion) and the glabella (the most prominent point on the frontal bone above the root of the nose), in the midline, more than two SD below the mean. Alternatively, an apparently decreased distance between the hairline and the glabella.
Depressed nasal ridge
MedGen UID:
334631
Concept ID:
C1842876
Finding
Lack of prominence of the nose resulting from a posteriorly-placed nasal ridge.
Widely spaced teeth
MedGen UID:
337093
Concept ID:
C1844813
Finding
Increased spaces (diastemata) between most of the teeth in the same dental arch.
Coarse facial features
MedGen UID:
335284
Concept ID:
C1845847
Finding
Absence of fine and sharp appearance of brows, nose, lips, mouth, and chin, usually because of rounded and heavy features or thickened skin with or without thickening of subcutaneous and bony tissues.
Broad forehead
MedGen UID:
338610
Concept ID:
C1849089
Finding
Width of the forehead or distance between the frontotemporales is more than two standard deviations above the mean (objective); or apparently increased distance between the two sides of the forehead.
Midface retrusion
MedGen UID:
339938
Concept ID:
C1853242
Anatomical Abnormality
Posterior positions and/or vertical shortening of the infraorbital and perialar regions, or increased concavity of the face and/or reduced nasolabial angle.
Thick eyebrow
MedGen UID:
377914
Concept ID:
C1853487
Finding
Increased density/number and/or increased diameter of eyebrow hairs.
Hypertrichosis
MedGen UID:
43787
Concept ID:
C0020555
Disease or Syndrome
Hypertrichosis is increased hair growth that is abnormal in quantity or location.
Nystagmus
MedGen UID:
45166
Concept ID:
C0028738
Disease or Syndrome
Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.
Retinal degeneration
MedGen UID:
48432
Concept ID:
C0035304
Finding
A nonspecific term denoting degeneration of the retinal pigment epithelium and/or retinal photoreceptor cells.
Impaired smooth pursuit
MedGen UID:
325176
Concept ID:
C1837458
Finding
An impairment of the ability to track objects with the ocular smooth pursuit system, a class of rather slow eye movements that minimizes retinal target motion.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
Follow this link to review classifications for Deficiency of alpha-mannosidase in Orphanet.

Professional guidelines

PubMed

Borgwardt L, Lund AM, Dali CI
Pediatr Endocrinol Rev 2014 Sep;12 Suppl 1:185-91. PMID: 25345101

Curated

Nilssen Ø, Stensland HM, Malm D
Eur J Hum Genet 2011 Jul;19(7) Epub 2011 Feb 2 doi: 10.1038/ejhg.2011.5. PMID: 21368911Free PMC Article

Recent clinical studies

Etiology

Abdul Ghani S, Burney S, Ul Hussain H, Abdul Wahid M, Mumtaz H
Int J Surg 2023 Sep 1;109(9):2882-2885. doi: 10.1097/JS9.0000000000000528. PMID: 37352513Free PMC Article
Guffon N, Tylki-Szymanska A, Borgwardt L, Lund AM, Gil-Campos M, Parini R, Hennermann JB
Mol Genet Metab 2019 Apr;126(4):470-474. Epub 2019 Jan 31 doi: 10.1016/j.ymgme.2019.01.024. PMID: 30792122
Gerards AH, Winia WP, Westerga J, Dijkmans BA, van Soesbergen RM
Clin Rheumatol 2004 Feb;23(1):40-2. Epub 2003 Nov 13 doi: 10.1007/s10067-003-0770-x. PMID: 14749981

Diagnosis

Abdul Ghani S, Burney S, Ul Hussain H, Abdul Wahid M, Mumtaz H
Int J Surg 2023 Sep 1;109(9):2882-2885. doi: 10.1097/JS9.0000000000000528. PMID: 37352513Free PMC Article
Guffon N, Tylki-Szymanska A, Borgwardt L, Lund AM, Gil-Campos M, Parini R, Hennermann JB
Mol Genet Metab 2019 Apr;126(4):470-474. Epub 2019 Jan 31 doi: 10.1016/j.ymgme.2019.01.024. PMID: 30792122
Borgwardt L, Lund AM, Dali CI
Pediatr Endocrinol Rev 2014 Sep;12 Suppl 1:185-91. PMID: 25345101
Olmez A, Nilssen O, Coşkun T, Klenow H
Turk J Pediatr 2003 Jan-Mar;45(1):46-50. PMID: 12718372
Mali JW, Bergers AM, Van Den Hurk JJ, Mier PD, Van De Staak WJ
Br J Dermatol 1976 Dec;95(6):627-30. doi: 10.1111/j.1365-2133.1976.tb07035.x. PMID: 795449

Therapy

Abdul Ghani S, Burney S, Ul Hussain H, Abdul Wahid M, Mumtaz H
Int J Surg 2023 Sep 1;109(9):2882-2885. doi: 10.1097/JS9.0000000000000528. PMID: 37352513Free PMC Article

Clinical prediction guides

Mali JW, Bergers AM, Van Den Hurk JJ, Mier PD, Van De Staak WJ
Br J Dermatol 1976 Dec;95(6):627-30. doi: 10.1111/j.1365-2133.1976.tb07035.x. PMID: 795449

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