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Genetic and Rare Diseases Information Center (GARD)

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Mannose-binding lectin protein deficiency


* Not a rare disease
Other Names for this Disease
  • Mannose-binding protein deficiency
  • MBL deficiency
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Your Question

My son was diagnosed with this last year. He has had multiple vaccinations. What are the actual numbers of how many Americans have this? Is there any work being done on finding a cure? Are there any ongoing studies? I know a little girl who has the same thing and she has had problems with her urinary tract but my son only had problems with his ears, nose and throat. Are these differences common? Any information would be greatly appreciated. Its very frustrating having so many questions and not many answers.

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

How common is mannose-binding lectin protein (MBL) deficiency?

Mannose-binding lectin protein deficiency is thought to be fairly common, with a 3% frequency in the general population.[1] The condition appears to be more common in certain populations; it may be present in about 5% of people of European descent and about 10% of sub-Saharan Africans.[2][3]
Last updated: 5/11/2012

Where can I find information about research studies and clinical trials involving treatments for mannose-binding lectin protein deficiency?

The U.S. National Institutes of Health, through the National Library of Medicine, developed to provide patients, family members, and members of the public with current information on clinical research studies. This site is updated regularly and may be checked often for updates. To find trials for mannose-binding lectin protein deficiency, click on the link above and use "mannose-binding lectin" as your search term. After you click on a study, review its "eligibility" criteria to determine its appropriateness. Use the study’s contact information to learn more.

You can also find relevant articles on mannose-binding lectin protein deficiency through PubMed, a searchable database of biomedical journal articles. Although not all of the articles are available for free online, most articles listed in PubMed have a summary available. To obtain the full article, contact a medical/university library or your local library for interlibrary loan. You can also order articles online through the publisher’s Web site. Using "mannose-binding lectin" as your search term should help you locate articles. Use the Advanced and Limits search features to narrow your search results. Click here to view a search.

The National Library of Medicine (NLM) Web site has a page for locating libraries in your area that can provide direct access to these journals (print or online). The Web page also describes how you can get these articles through interlibrary loan and Loansome Doc (an NLM document-ordering service). You can access this page at the following link: You can also contact the NLM toll-free at 888-346-3656 to locate libraries in your area.
Last updated: 5/11/2012

What are the signs and symptoms of mannose-binding lectin protein (MBL) deficiency?

Individuals with MBL deficiency are prone to recurrent infections, including infections of the upper respiratory tract and other body systems. Affected individuals may also contract more serious infections such as pneumonia and meningitis. The signs and symptoms associated with MBL deficiency vary among affected individuals; symptoms may depend upon the type of infections present as well as their frequency and severity.[3]

Infants and young children with MBL deficiency seem to be more susceptible to infections, but adults can also develop recurrent infections.[3] Other individuals more susceptible to infection include cancer patients undergoing chemotherapy and organ-transplant patients receiving immunosuppressive drugs (particularly recipients of liver transplants).[2]

There has been much research regarding the role of MBL deficiency in increasing the risk for complications such as infections in those who have both MBL deficiency and other conditions, such as cystic fibrosis; autoimmune diseases such as rheumatoid arthritis and lupus; AIDS; atherosclerosis; and people on chemotherapy for the treatment of blood cancers (e.g., leukemia, lymphoma) and other blood disorders (e.g., myelodysplastic syndromes).[1] However, the results of these studies have been conflicting.
Last updated: 5/11/2012