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IRAK-4 deficiency
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

IRAK-4 deficiency

IRAK-4 deficiency is a rare inherited immune system disorder that causes recurrent, life-threatening infections by pyogenic bacteria, particularly in infancy and childhood.

Overview

IRAK-4 deficiency is an inherited disorder of the immune system, classified as a primary immunodeficiency. This condition leads to recurrent infections by a subset of bacteria known as pyogenic bacteria (bacteria that cause the production of pus). The most common infections are caused by Streptococcus pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa.

Most individuals experience their first bacterial infection before age 2. While these infections can be life-threatening during infancy and childhood, they typically become less frequent with age. Many affected individuals do not develop a high fever in response to these infections, even when they are severe.

Symptoms

Invasive bacterial infections are common and may involve:

  • The blood (septicemia)
  • The membrane covering the brain and spinal cord (meningitis)
  • The joints (leading to inflammation and arthritis)
  • Internal organs (causing tissue breakdown and abscesses)

Affected individuals may also experience localized infections of the skin or eyes.

Causes

The condition is caused by mutations in the IRAK4 gene. This gene provides instructions for making a protein essential for the innate immune response—the body's early, nonspecific defense against pathogens. The IRAK-4 protein is part of a signaling pathway that recognizes foreign invaders and initiates inflammation to fight infection. Mutations result in a nonfunctional protein or a total lack of the protein, preventing the immune system from triggering the necessary inflammatory response.

Inheritance

This condition is inherited in an autosomal recessive pattern, meaning both copies of the gene in each cell must have mutations. Parents of an affected individual each carry one copy of the mutated gene but typically do not show signs or symptoms of the condition.

Frequently Asked Questions

IRAK‑4 is critical for signaling that triggers the release of inflammatory cytokines, including those that raise body temperature. Without functional IRAK‑4, the immune system fails to mount the typical febrile response, so infections may progress silently. Parents should watch for other signs such as lethargy, poor feeding, or localized redness and seek care immediately.;Are routine childhood vaccines safe for a child with IRAK‑4 deficiency, and should any be avoided?::Most live‑attenuated vaccines (e.g., MMR, varicella, oral polio) are contraindicated because the child’s innate immune response is impaired. Inactivated vaccines (e.g., DTaP, Hib, pneumococcal conjugate, influenza) are generally safe and recommended. A vaccine schedule should be coordinated with an immunologist to ensure protection without risking infection.;What is the typical course of treatment when a child with IRAK‑4 deficiency develops a bacterial infection?::Prompt intravenous antibiotics covering common pyogenic organisms (Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa) are started empirically. Once culture results are available, therapy is narrowed. Because the patient may not have a fever, clinicians rely on clinical signs and laboratory markers (CRP, procalcitonin). Long‑term prophylaxis with oral antibiotics (e.g., amoxicillin‑clavulanate) and regular IVIG can reduce infection frequency.;How can families prepare for potential infections in a child with IRAK‑4 deficiency?::Keep a list of emergency contacts and a written action plan for suspected sepsis (e.g., call 911, bring the child to the nearest ER). Ensure all caregivers are aware of the child’s condition and the importance of early medical evaluation. Maintain a clean environment, avoid exposure to sick contacts, and keep up‑to‑date on inactivated vaccines. A home health nurse can assist with IVIG infusions and monitoring.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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