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Genetic and Rare Diseases Information Center (GARD)

Alpha mannosidosis type 2

Other Names for this Disease
  • Alpha-mannosidosis adult-onset form
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

How severe is it? Does it stabilize? Are there factors which exacerbate it? Are there treatments to slow or stop progression? What are signs and symptoms of end stage disease?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is alpha mannosidosis type 2?

Alpha mannosidosis type 2 is a lysosomal storage disorder.  Signs and symptoms develop as a result of the toxic build-up of sugars (i.e., mannose-containing oligosaccharides) in the cells of the body. People with this disorder tend to develop bone abnormalities and muscle weakness by age 10. Signs and symptoms vary, but often include mild to moderate intellectual disability, hearing loss, weakened immune system, distinctive facial features, and cerebellar disorders (e.g., ataxia). Symptoms slowly worsen over time. This disorder is caused by a mutation in MAN2B1 and is inherited in an autosomal recessive fashion.[1][2]
Last updated: 10/1/2013

What are the signs and symptoms of alpha mannosidosis type 2?

More common signs and symptoms of alpha mannosidosis type 2 include:[1][2]

Bone abnormalities
Muscle weakness
Intellectual disability
Developmental delays (e.g., motor and speech)
Hearing loss
Weakened immune system
Cerebellar disorders (e.g., ataxia)
Occasional psychiatric symptoms (e.g., depression, anxiety, or hallucinations)
Enlarged liver and spleen (with normal function)

People with alpha-mannosidosis type 2 often have distinct facial features, including large head size, large forehead, low hair line, rounded eyebrows, large ears, wide spaced teeth, overgrown gums, large tongue, protruding jaw, and flattened bridge of the nose.

Last updated: 10/1/2013

Are there factors that can worsen symptoms of alpha mannosidosis type 2?

Currently, little is known regarding specific factors that may adversely affect disease severity. We were unable to find information regarding specific diets, activities, or life-style factors that can worsen prognosis.
Last updated: 10/1/2013

How might alpha mannosidosis type 2 be treated?

Current treatment options for alpha mannosidosis may include bone marrow transplant or peripheral blood stem cell transplantation. Enzyme replacement therapy may be an additional treatment option in the future.[2]

Treatments to address individual symptoms are recommended as needed, such as vaccinations, antibiotics, hearing aids, glasses, orthopedic and other assistive devices, educational interventions, and speech therapy. Regular follow-up to monitor health and treatment response is advised.[2]

Further detailed information on treatment is available at the following link to GeneReviews.

Last updated: 10/18/2013

What is the typical long-term outlook for people with alpha mannosidosis type 2?

There is limited information regarding long-term outlook for people with alpha mannosidosis. Much of the literature describes cases in children. Frequency of infections, such as colds, pneumonia, ear infection, and stomach flu is often worse in early childhood and improves with age. Muscle weakness and central nervous system disease (e.g., cerebellar disorders) tend to become evident in adolescence to early adulthood. These symptoms tend to slowly worsen overtime. Intellectual disability is common and adults tend to have an IQ of 60-80. Intellectual disability remained stable in some, but not all reported cases.  Bone involvement is highly variable, but symptoms may decrease with age. While people with alpha mannosidosis have lived well into adulthood, there is very limited data regarding life expectancy and cause of death in affected adults.[2][3]
Last updated: 10/1/2013

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:
Last updated: 5/18/2016

Other Names for this Disease
  • Alpha-mannosidosis adult-onset form
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.