Mannose-binding lectin protein deficiency

Title

Not a rare disease

Other Names:

MBL deficiency; Mannose-binding protein deficiency

Categories:

Metabolic disorders

Summary Summary

Mannose-binding lectin protein (MBL) deficiency is a complement component deficiency that alters the function of the body's immune system. This condition usually causes frequent and sometimes severe infections in infants and young children.^[1] This deficiency can occur as a result of one or more variations in the MBL2 gene, which codes for the MBL protein. A lack of this protein can cause this condition, but is likely further influenced by other genetic and environmental factors.^[2]

Last updated: 4/9/2012

Symptoms Symptoms

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).^[4]

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

Cause Cause

MBL deficiency can occur as a result of one or more variations in the MBL2 gene, which codes for the MBL protein. A lack of this protein can cause this condition, but it is likely further influenced by other genetic and environmental factors that are currently poorly understood.^[2]

The mannose-binding lectin (MBL) protein is excreted by the liver and is part of our innate immune defense. This protein binds to sugars on the surface of microorganisms to signal their destruction and triggers one of the major complement cascades called the “mannose-binding lectin (MBL) pathway.” Complement cascades are made up of proteins that work together to destroy bacteria and other antigens. The mannose binding protein circulates in the blood in an inactive form. When it is activated it sets in motion a domino effect where each component of the mannose-binding lectin pathway takes its turn in a precise chain of steps. The end products from the cascade are able to destroy invading bacteria and other antigens.^[5]

More information on immune system responses can be found at the following link from MedlinePlus, the National Library of Medicine Web site designed to help you research your health questions.
http://www.nlm.nih.gov/medlineplus/ency/article/000821.htm

Last updated: 4/9/2012

Treatment Treatment

Currently, there are no specific therapies available for mannose-binding lectin protein deficiency. Fresh frozen plasma may be used in emergencies to replace complement components. Routine vaccinations may be recommended (e.g., meningococcal vaccine, pneumococcal vaccine). Because a certain gene has been found to cause this condition, gene therapy may be a viable treatment in the future.^[1]

Last updated: 4/9/2012

Prognosis Prognosis

Mannose-binding lectin protein (MBL) deficiency is a common immunodeficiency that is thought to have a general role in increasing a person's risk for developing respiratory tract infections. Our search of the literature did not indicate that there is an overall reduced life expectancy in people with MBL deficiency alone.^[2]

MBL deficiency may play a bigger role in the risk of infection in people who already have an increased risk for respiratory tract infections, such as people with cystic fibrosis.^[2] People with cystic fibrosis are often prone to severe recurrent lung infections and respiratory failure is the most common cause of death. It has been estimated that MBL deficiency can reduce life expectancy by 5 to 8 years in people with cystic fibrosis.^[6] In addition, there has been much study regarding the role of MBL deficiency in increasing the risk for serious complications in people who also have autoimmune diseases or AIDS; and in people on chemotherapy for treatment of blood cancers and other blood disorders (e.g., myelodysplastic syndromes). However, studies of the complications and impacts on life expectancy in people with MBL deficiency and these conditions have had conflicting results.^[7]^[8]^[9]^[10]^[11]^[12]

You can find a comprehensive summary of the literature on this topic at the following link to Online Mendelian Inheritance in Man (OMIM). Although the language is technical, OMIM is considered a comprehensive source of information. You may benefit from discussing this information with a medical professional.
http://us-east.omim.org/entry/614372

Last updated: 1/9/2012

Organizations Organizations

Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD. Suggest an organization to add.

Organizations Supporting this Disease

American Autoimmune Related Diseases Association (AARDA)
22100 Gratiot Avenue Eastpointe
East Detroit, MI 48201-2227
Toll-free: 800-598-4668
Telephone: 586-776-3900
Fax: 586-776-3903
E-mail: aarda@aarda.org
Website: http://www.aarda.org/
Immune Deficiencies Foundation Australia
PO Box 969
Penrith NSW 2751
Australia
Telephone: 800-100-198
E-mail: info@idfa.org.au
Website: http://www.idfa.org.au/
Immune Deficiency Foundation
110 West Road, Suite 300
Towson, MD 21204
Toll-free: 800-296-4433
Fax: 410-321-9165
E-mail: idf@primaryimmune.org
Website: http://www.primaryimmune.org/

Learn More Learn More

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

Genetics Home Reference (GHR) contains information on Mannose-binding lectin protein deficiency. This website is maintained by the National Library of Medicine.
Entrez Gene, a searchable database of genes devloped by the National Center for Biotechnology Information (NCBI), has a information page on the MBL2 gene. Click on Entrez Gene to view this information page.

In-Depth Information

Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
PubMed is a searchable database of medical literature and lists journal articles that discuss Mannose-binding lectin protein deficiency. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles

Eisen DP. Mannose-Binding Lectin Deficiency and Respiratory Tract Infection. J Innate Immun. 2010 Feb;2:114-122.

GARD Answers GARD Answers

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Our child was recently diagnosed with 10q22.3q23.2 microdeletion syndrome. She was also diagnosed with mannose binding lectin deficiency. With these both stemming from Chromosome 10 is there any additional information on these specific deletions and if there is a relation between the two? Additionally, is there any information on what possible health risks we should look out for (crohn's disease, heart, liver etc). Thank you for your time. See answer
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. See answer
My child was just diagnosed with mannose binding lectin protein deficiency. There is alot of information out there, but most is confusing. Are there any statistics on how many people have this? Do they normally live an average life span if you can keep them healthy? Will my future grandchildren be at risk for inheriting it? Is there possibly any link between this disease and taking levaquin during pregnancy? See answer
My wife has been diagnosed with MBL deficiency. Can you provide us with information on this condition? See answer

References References

Agrawal R. Complement deficiency. eMedicine. May 2009; http://emedicine.medscape.com/article/886128-overview. Accessed 1/9/2012.
Eisen DP. Mannose-binding lectin deficiency and respiratory tract infection. J Innate Immun. February 2010; http://content.karger.com/ProdukteDB/produkte.asp?Aktion=ShowPDF&ArtikelNr=000228159&Ausgabe=253949&ProduktNr=234234&filename=000228159.pdf. Accessed 1/9/2012.
Mannose-binding lectin deficiency. Genetics Home Reference. March 2012; http://ghr.nlm.nih.gov/condition/mannose-binding-lectin-deficiency.
Mannose-binding protein deficiency. Online Mendelian Inheritance of Man (OMIM). December 2011; http://us-east.omim.org/entry/614372. Accessed 1/9/2012.
Immune system, Complement system. National Institute of Allergy and Infectious Disease. October 2008; http://www.niaid.nih.gov/topics/immuneSystem/immuneCells/complementSystem.htm. Accessed 1/9/2012.
Ezekowitz RA. Role of the mannose-binding lectin in innate immunity. Journal of Infectious Diseases. 2003 Jun 15;
Tsutsumi A, Takahashi R, Sumida T. Mannose binding lectin: genetics and autoimmune disease. Autoimmun Rev. 2005 Jul; http://www.ncbi.nlm.nih.gov/pubmed/16081027. Accessed 5/4/2011.
Troelsen LN, Garred P, Jacobsen S. Mortality and predictors of mortality in rheumatoid arthritis--a role for mannose-binding lectin?. J Rheumatol. 2010 Mar;
Vekemans M et al. Low mannose-binding lectin concentration is associated with severe infection in patients with hematological cancer who are undergoing chemotherapy. Clin Infect Dis. 2007 Jun 15;
Hoeflich C, et al. Clinical manifestation of mannose-binding lectin deficiency in adults independent of concomitant immunodeficiency. Hum Immunol. 2009 Oct;
Dahl M, Tybjaerg-Hansen A, Schnohr P, Nordestgaard BG. A population-based study of morbidity and mortality in mannose-binding lectin deficiency. J Exp Med. 2004 May 17;
Turner MW. The role of mannose-binding lectin in health and disease. Mol Immunol. 2003 Nov;