Diagnosing Alpha-Mannosidosis

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

Diagnosing Alpha-Mannosidosis

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 gene.2 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

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

diagnostic test
Step 2
From the Symptoms to the
Management of Alpha-Mannosidosis

Step 2
From the Symptoms to the
Management of Alpha-Mannosidosis

  1. Guffon, N. et al. Recognition of alpha-mannosidosis in paediatric and adult patients: Presentation of a diagnostic algorithm from an international working group. Molecular Genetics and Metabolism 126, 470–474 (2019).
  2. Ceccarini, M. R. et al. Alpha-Mannosidosis: Therapeutic Strategies. International Journal of Molecular Sciences 19, 1500 (2018).
  3. Ficicioglu, C. & Stepien, K. M. Alpha-Mannosidosis. in GeneReviews® (eds. Adam, M. P. et al.) (University of Washington, Seattle, Seattle (WA), 1993).