The practitioners

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.

In young patients, the presence of hearing impairment and/or speech delay are the main signs that should prompt your doctor to look for additional symptoms.1

Adolescent and older patients may have different signs and symptoms, and mental retardation and motor impairment might warrant further investigation.1

In both younger and older patients, a definite diagnosis may involve testing for the presence of certain sugars in urine or blood serum, and genetic testing may be used to confirm suspicion.1

Your doctor can provide you with further information and recommend the right tests should alpha mannosidosis be suspected in any individual.

Diagnostic test

Your doctor may also refer the individual to see a metabolic disease specialist and/or clinical geneticist, who are more familiar with this rare condition. These specialists can recommend the appropriate tests to carry out to confirm that a person has alpha mannosidosis. In some cases, genetic testing may be done. Alpha mannosidosis is caused by what is called a recessive gene2. Each pregnancy of a couple in which both partners are heterozygous for a disease-causing mutation of the MAN2B1 gene has a 25% chance of having an affected child, a 50% chance of having an unaffected child who is a carrier, and a 25% chance of having an unaffected child who is not a carrier.3


Alpha Mannosidosis diagnosis

There is a two of three chance that unaffected brothers and sisters of those affected by alpha mannosidosis will be carriers of the disease, but normal otherwise. However, since the disease is so rare, the chance of having a partner who is another carrier is slight, unless the individuals belong to the same family.3

  1. Guffon N, et al. Mol Gen Metab. 2019;126:470.
  2. Ceccarini MR, et al. Int J Mol Sci. 2018;19:1500.
  3. Alpha-mannosidosis mutation database. Available at:

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.