MyD88 deficiency

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What is MyD88 deficiency?

MyD88 deficiency is an inherited disorder of the immune system (primary immunodeficiency). This primary immunodeficiency affects the innate immune response, which is the body's early, nonspecific response to foreign invaders (pathogens). MyD88 deficiency leads to abnormally frequent and severe infections by a subset of bacteria known as pyogenic bacteria. (Infection with pyogenic bacteria causes the production of pus.) However, affected individuals have normal resistance to other common bacteria, viruses, fungi, and parasites. The most common infections in MyD88 deficiency are caused by the Streptococcus pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa bacteria. Most people with this condition have their first bacterial infection before age 2, and the infections can be life-threatening in infancy and childhood. Infections become less frequent by about age 10.

Children with MyD88 deficiency develop invasive bacterial infections, which can involve the blood (septicemia), the membrane covering the brain and spinal cord (meningitis), or the joints (leading to inflammation and arthritis). Invasive infections can also cause areas of tissue breakdown and pus production (abscesses) on internal organs. In addition, affected individuals can have localized infections of the ears, nose, or throat. Although fever is a common reaction to bacterial infections, many people with MyD88 deficiency do not at first develop a high fever in response to these infections, even if the infection is severe.

How common is MyD88 deficiency?

The prevalence of MyD88 deficiency is unknown. At least 24 affected individuals have been described in the medical literature.

What genes are related to MyD88 deficiency?

MyD88 deficiency is caused by mutations in the MYD88 gene, which provides instructions for making a protein that plays an important role in stimulating the immune system to respond to bacterial infection. The MyD88 protein is part of a signaling pathway that is involved in early recognition of pathogens and the initiation of inflammation to fight infection. This signaling pathway is part of the innate immune response.

Mutations in the MYD88 gene lead to the production of a nonfunctional protein or no protein at all. The loss of functional MyD88 protein prevents the immune system from triggering inflammation in response to pathogens that would normally help fight the infections. Because the early immune response is insufficient, bacterial infections occur often and become severe and invasive.

Researchers suggest that as the immune system matures, other systems compensate for the loss of MyD88 protein, accounting for the improvement in the condition that occurs by adolescence.

How do people inherit MyD88 deficiency?

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Where can I find information about diagnosis or management of MyD88 deficiency?

These resources address the diagnosis or management of MyD88 deficiency and may include treatment providers.

Genetic Testing Registry: Myd88 deficiency

You might also find information on the diagnosis or management of MyD88 deficiency inEducational resources and Patient support.

General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.

To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.

Where can I find additional information about MyD88 deficiency?

You may find the following resources about MyD88 deficiency helpful. These materials are written for the general public.

MedlinePlus - Health information (4 links)
Additional NIH Resources - National Institutes of Health
National Institute of Allergy and Infectious Diseases
Educational resources - Information pages (3 links)
Patient support - For patients and families (3 links)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

Genetic Testing Registry - Repository of genetic test information (1 link)
PubMed - Recent literature
OMIM - Genetic disorder catalog

What other names do people use for MyD88 deficiency?

MYD88 deficiency
pyogenic bacterial infections due to MyD88 deficiency

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines and How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about MyD88 deficiency?

Ask the Genetic and Rare Diseases Information Center

Where can I find general information about genetic conditions?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding MyD88 deficiency?

arthritis ; autosomal ; autosomal recessive ; bacteria ; breakdown ; cell ; deficiency ; fever ; gene ;immune response ; immune system ; immunodeficiency ; infection ; inflammation ; inherited ;prevalence ; protein ; receptor ; recessive ; septicemia ; tissue

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

References (6 links)

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook