Disease Directory Alpha-Mannosidosis
Metabolic

Alpha-Mannosidosis

Also known as: MAN2B1 deficiency, lysosomal alpha-mannosidase deficiency

Prevalence

1-9 per 1,000,000 (Orphanet)

Onset

Childhood, Adolescent

Type

Autosomal recessive genetic

Gene

MAN2B1

About Alpha-Mannosidosis

Alpha-mannosidosis is a lysosomal storage disorder caused by deficiency of lysosomal alpha-mannosidase (MAN2B1), which is required to break down mannose-rich oligosaccharides. Accumulation of these glycoprotein fragments in cells throughout the body causes intellectual disability, recurrent infections due to immune dysfunction, hearing loss, and skeletal abnormalities. Velmanase alfa (Lamzede) is an approved enzyme replacement therapy for non-neurological manifestations.

Common Clinical Features

Intellectual disability Recurrent infections Hearing loss Coarse facial features Ataxia Skeletal abnormalities Psychiatric symptoms

Clinical Trial Eligibility Tips

What to know before applying to Alpha-Mannosidosis trials.

Velmanase alfa (Lamzede) is approved — trials may focus on CNS outcomes, higher-dose regimens, or next-generation approaches

Urinary oligosaccharide excretion pattern is the diagnostic biomarker required for trial documentation

Neuropsychological testing battery results are key eligibility and outcome measures

Hematopoietic stem cell transplantation has been used in some patients — transplant status affects eligibility for ERT or gene therapy trials

Patient Resources

Patient Organization

International Mannosidosis and Related Diseases (ISMRD)

Visit website ↗

Natural History Registry

ISMRD Global Patient Registry

Join registry ↗

Orphanet

European reference resource for rare diseases (ORPHA:61)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

Search NORD ↗

Find recruiting Alpha-Mannosidosis trials

Search 500,000+ studies from ClinicalTrials.gov, filtered for Alpha-Mannosidosis. Updated daily.

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