Recognition of alpha-mannosidosis in paediatric and adult patients: Presentation of a diagnostic algorithm from an international working group

Mol Genet Metab. 2019 Apr;126(4):470-474. doi: 10.1016/j.ymgme.2019.01.024.

PMID: 30792122

N Guffon, A Tylki-Szymanska, L Borgwardt

Highlights: With the aim of developing a diagnostic algorithm for alpha-mannosidosis an international panel of experts met to reach a consensus by applying the nominal group technique.

Abstract:

Background: A deficiency of alpha-mannosidase results in the extremely rare progressive lysosomal storage disorder known as alpha-mannosidosis. A timely diagnosis of the disease has the potential to affect patient outcomes since early prevention measures can be started. However, there is currently no globally accepted algorithm for the diagnosis of the condition.

Objective: An international panel of specialists gathered with the goal of creating a diagnostic algorithm for alpha-mannosidosis. They used the nominal group technique to come to a decision.

Results: Alpha-mannosidosis diagnostic algorithms have been proposed in two different ways, one for patients under 10 and one for those over 10. The primary symptoms that should encourage the physician to search for other symptoms that could lead to more diagnostic information in younger children are hearing loss and/or delayed speech. Older patients present differently clinically, and the existence of motor impairment progression, mental retardation, and/or psychiatric manifestations should cause the physician to check for further symptoms. When there is a suspicion of disease, both younger and older patients should receive either extra metabolic monitoring or a referral for testing. Oligosaccharides in serum or urine were used as the first step in the screening process; however, in some centers, enzymatic activity may also be the method of choice. The last confirmation procedure should involve molecular testing.

Conclusion: The discovered methods are simple to implement in a number of contexts and may support early alpha mannosidosis diagnosis and therapy.

Keywords: Algorithm, Alpha-mannosidosis, Diagnosis, Lysosomal storage disorder, Symptoms