Symptoms & diagnosis

General Management of Alpha Mannosidosis

Non-specific management1

  • In general, the approach to the patients is proactive, with the aim of preventing emerging complications. After a full physical examination, physicians should focus on the known complications of Alpha Mannosidosis, such as hydrocephalus, otitis media, hearing loss, dental caries, joint symptoms, kyphoscoliosis, and mental state.2
  • A multidisciplinary care team is key to patient care. This typically includes an ophthalmologist, an otolaryngologist, an audiologist and a neurophysiologist.3 Clinical evaluations include blood tests and radiological evaluations, with radiographs of the head, spine, knees or other areas of the skeleton displaying symptoms.4

Management of Hydrocephalus5

  • Early diagnosis with measurement of head circumference, diagnosis with ultrasound, skull radiographs or computed tomography (CT).

Management of Otitis Media6

  • Diagnosis is simple, and insertion of pressure-equalizing tubes reduces the potential impact of reduced hearing. Hearing aids are often deployed and are used as an adjunct to speech therapy.


  • Dental caries can be frequent in these patients because of reduced dental quality combined with tooth grinding or acid reflux from the stomach. Regular dental support and good dental hygiene is essential.

Joint status8

  • Joint pathology is monitored throughout the course of the disease. A number of orthopedic surgical procedures may be needed throughout the patients lifetime.

Mental state9

  • Mental state can be monitored with various tests, such as the Wechsler test. Nonverbal tests can be deployed to compensate for the hearing deficit.

Patient organisations

ISMRD is the international support group for Alpha Mannosidosis
The Society for Mucopolysaccharide Diseases, .
Other MPS groups around the world will also offer support. MetabERN is a network of healthcare providers and patient groups across Europe, providing support for people with inherited metabolic disorders such as Alpha Mannosidosis.
Lysosomal Diseases New Zealand is the support group for families in New Zealand.

Specific Treatment for Alpha Mannosidosis

Hematopoietic stem cell transplantation (HSCT)10

Rationale for treatment: with this condition, all cells are without α-mannosidase activity. The rationale for HSCT in this setting is that enzyme-producing donor cells repopulate the host tissues and transfer enzyme to nearby enzyme-deficient host cells.

  • The outcomes from HSCT have been reported as variable with mixed reports of the neurocognitive impact of the therapy.1112
  • A number of unpublished HSCTs have been performed.13However, in 2004, results were published for four patients, aged 3 to 23 years, who had undergone the procedure, suggesting that intellectual function in these patients stabilised, with improvement in adaptive skills and verbal memory function (some with improvements in hearing for speech frequencies only).14
  • The possible benefits of HSCT must be weighed against the overall risk of the procedure, related to morbidity and mortality.15 The benefits are greater in younger patients, before the disease has progressed further.16,17
  • Transplant-related complications are more frequent and severe in older patients, which means HSCT is more of an option in the first years of life. This makes early identification of affected patients critical.18

Specific Treatment for Alpha Mannosidosis

Enzyme Replacement Therapy

Enzyme replacement therapy (ERT) is a therapeutic alternative in a number of lysosomal storage diseases.19
An ERT is approved for use in the European Union.20


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