What is Alpha Mannosidosis?

Alpha Mannosidosis is a rare inherited disease that can cause children and adults to suffer from skeletal deformities, coarse facial features, hearing loss, cognitive disabilities, problems with the immune system (which may mean, for example, you catch infections more readily), mental health and behavioural issues.1

Signs of Alpha Mannosidosis2

Alpha Mannosidosis symptoms

Hydrocephalus
Persons may have fluid build-up in the brain

Hearing loss
Almost all individuals suffering from alpha mannosidosis will have some degree of hearing loss

Skeletal abnormalities in many individuals include scoliosis, or curvature of the spine

Immunodeficiency and autoimmunity recurrent infection, especially in the first decade of life

Mental functions individuals with alpha mannosidosis usually have some signs of learning disability, which can be mild or more severe. Such signs include difficulty in learning to speak

Facial features tend to be coarse

Persons may have polyarthropathy, a disease involving multiple joints

Motor control
Persons with alpha mannosidosis may often appear to be clumsy, which is cause by muscleweakness and abnormalities in their joints

First presentation

Recurrent ear infections associated with hearing loss.3 Progressive impairment of mental functions, speech and motor control.4 Hydrocephalus can be present in the first year of life.5

2nd-3rd decade of life

Muscular weakness and ataxia, skeletal abnormalities and destructive poly-arthropathy.6
Neuro-cognitive development is usually arrested and psychiatric disorders may also manifest.7

In adulthood

Patients are unable to achieve complete social independence.8
There are very limited data regarding life expectancy in adults.

Timely diagnosis of alpha mannosidosis is important as it can influence how well the individual does in the long-term as therapies should be initiated as soon as possible.9

Your doctor can use a number of very simple tests to diagnose Alpha Mannosidosis, including:
Urine
sample10

This will measure oligosaccharide levels in urine. High levels will be suggestive of Alpha Mannosidosis

Blood
sample11

A small sample of blood is taken to measure the presence of mannosidase enzyme in blood cells. This can be used to confirm a diagnosis.

Genetic
testing12

A diagnosis of Alpha Mannosidosis can also be confirmed through genetic testing, which can detect the mutation in the gene that causes the disorder.

Caring for persons with Alpha Mannosidosis

Ideally, the individual with alpha-mannosidosis will be followed by a team of medical specialists who can help determine the specific needs of each person and help suggest the most appropriate solutions.13 For examples:

Tips for helping those with Alpha Mannosidosis14

The home environment should be adequately prepared to meet these needs, such as

The use of ramps to allow wheelchair access


Fixing any hazards for walking and install non-slip flooring in the bathroom and kitchen


Increasing the amount of light

Moreover, individuals will need early educational intervention for development of social skills, speech therapy and special education to maximise learning.

Thus, caring for someone with alpha mannosidosis can be extremely challenging. If you are caring for someone with the disease, always keep in close contact with the specialist who is managing the person, as they can provide specific advice depending on the individual needs.

  1. Malm D & Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  2. Malm D, Nilssen O. Alpha-Mannosidosis. NCBI. Available at: https://www.ncbi.nlm.nih.gov/books/NBK1396/.)
  3. Malm D & Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  4. Malm D & Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  5. Malm D & Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  6. Malm D & Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  7. Malm D & Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  8. Malm D & Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  9. Guffon N, et al. Mol Gen Metab. 2019;126:470.
  10. Malm D &Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  11. Malm D &Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  12. Malm D &Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  13. Malm D &Nilssen ø. Alpha-mannosidosis. Orphanet J Rare Dis 2008;3:21
  14. Malm D, Nilssen O. Alpha-Mannosidosis. NCBI. Available at: https://www.ncbi.nlm.nih.gov/books/NBK1396/.)

The information on this website is intended only to provide knowledge of Alpha Mannosidosis disease health topics. This information should not be used in place of advice from your GP or other healthcare professional. If in doubt please contact your doctor for advice. This website has been produced by Chiesi Pharmaceuticals. The website has been developed in accordance with industry and legal standards to provide information for healthcare professionals and the general public about Alpha Mannosidosis disease health topics. Chiesi Pharmaceuticals makes every reasonable effort to include accurate and current information. However, the information provided in this website is not exhaustive.