Chronic granulomatous disease is a rare inherited condition that affects how the body fights certain infections. Understanding when and how to get tested can make a significant difference in managing this lifelong condition and protecting your health.
Introduction: Who Should Undergo Diagnostics
If you or your child experience frequent bacterial or fungal infections that seem more serious than typical infections, it may be time to talk to a doctor about testing for chronic granulomatous disease. Most people with this condition are diagnosed during childhood, usually before age five, but some individuals may not show symptoms until they are teenagers or even adults. Early diagnosis is important because it allows doctors to start treatment that can help prevent infections before they become severe.[1]
You should consider seeking diagnostic testing if you notice a pattern of recurring infections, especially if these infections affect the lungs, skin, liver, or lymph nodes. Common warning signs include pneumonia that happens multiple times, skin infections that create boils or sores that do not heal, and abscesses in various organs. Some people develop a serious type of fungal pneumonia after being exposed to dead leaves, mulch, or hay, which is a red flag for this condition.[1][3]
Children and adults with chronic granulomatous disease, or CGD, typically experience a serious bacterial or fungal infection every few years. Between infections, they may appear completely healthy. However, if your child has had unexplained fevers, persistent runny nose, chest pain when breathing, swollen lymph nodes, or ongoing stomach problems like diarrhea and bloody stools, these symptoms warrant a conversation with your healthcare provider about possible testing.[1][2]
Family history plays a crucial role in deciding who should undergo diagnostics. Because CGD is a genetic condition that runs in families, anyone who has a family member diagnosed with CGD should discuss testing with their doctor. This is especially important for parents who are planning to have children, as genetic testing can reveal whether they carry the gene mutation that causes this disease.[2][5]
Women who are carriers of the X-linked form of CGD should also be monitored. These women may have autoimmune problems, like lupus of the skin, and sometimes may have serious infections themselves. Following the function of certain white blood cells called neutrophils is important for female carriers, as this can change over time and lead to an increased risk of CGD symptoms, including infections and inflammatory bowel disease.[5][10]
Diagnostic Methods: How CGD Is Identified
Diagnosing chronic granulomatous disease involves several steps that help doctors confirm whether your immune system is working properly. The process typically begins with your healthcare provider reviewing your medical history and family history, followed by a physical examination. During the physical exam, doctors look for signs of inflammation and granulomas, which are masses of cells that develop at sites of inflammation or infection in people with CGD.[2][9]
The most important and commonly used test for diagnosing CGD is called the dihydrorhodamine 123 test, or DHR test. This test measures how well a specific type of white blood cell, called a neutrophil, is functioning. Neutrophils are part of your immune system’s first line of defense against infections. In people with CGD, these cells cannot produce the chemicals needed to kill certain bacteria and fungi. The DHR test can detect this problem by measuring whether neutrophils are making the toxic substances they need to fight infections.[9][21]
Other neutrophil function tests may also be used to see how well these white blood cells are working. These tests help doctors understand whether your immune cells can properly attack and destroy harmful bacteria and fungi. Because people with CGD have neutrophils that do not produce hydrogen peroxide and other necessary chemicals, these function tests can reveal the specific defect in the immune system.[2][5]
Once neutrophil function tests suggest CGD, genetic testing is performed to confirm the diagnosis and identify which specific gene is affected. CGD can be caused by mutations in one of five different genes: CYBB, CYBA, NCF1, NCF2, or NCF4. Each of these genes provides instructions for making parts of an enzyme complex called NADPH oxidase, which plays an essential role in helping white blood cells kill bacteria and fungi. Genetic testing can determine exactly which gene mutation is causing the disease, which helps doctors understand what type of CGD you have and how it might affect your family members.[3][9]
There are two main types of CGD based on the gene involved. The most common type is called X-linked CGD, which involves a mutation in the CYBB gene located on the X chromosome. This type affects almost exclusively males and accounts for about 70 percent of CGD cases in the United States. The other types are called autosomal recessive CGD, where mutations in the CYBA, NCF1, NCF2, or NCF4 genes cause the disease. In autosomal recessive CGD, males and females are equally affected.[2][5]
If you already have children and one of them has been diagnosed with CGD, prenatal testing is available for future pregnancies. This testing can diagnose CGD before a baby is born, allowing families to prepare and plan for the care their child may need. Prenatal testing involves examining cells from the developing baby to check for the gene mutations that cause CGD.[9][21]
Blood tests are another important part of the diagnostic process. Doctors may order blood tests to check for signs of infection, measure liver function, and assess how well your bone marrow is producing immune cells. People with CGD can develop liver function test abnormalities, and blood tests help monitor these changes. Additionally, because chronic inflammation and frequent infections can affect bone marrow function, blood tests help doctors understand whether the disease is impacting the production of important blood cells.[2][13]
Imaging tests may be used to look for granulomas and abscesses in various parts of the body. These tests can include X-rays, computed tomography scans (CT scans), magnetic resonance imaging (MRI), or ultrasounds. Granulomas can form in the lungs, liver, stomach, intestines, and other organs, and imaging helps doctors see where these masses are located and how large they are. In some cases, granulomas can become so large that they block the bowel or the urinary tract, requiring medical attention.[2][5]
If a specific infection is suspected, doctors may perform additional tests to identify the exact bacteria or fungus causing the illness. This can involve taking samples of blood, sputum (mucus from the lungs), or tissue from infected areas. Identifying the specific pathogen helps doctors choose the most effective antibiotics or antifungal medications for treatment. People with CGD are particularly susceptible to infections from catalase-positive bacteria and certain fungi like Aspergillus and Candida species.[4][8]
Diagnostics for Clinical Trial Qualification
When considering enrollment in clinical trials for chronic granulomatous disease, specific diagnostic tests and criteria are used to determine whether a patient is eligible to participate. Clinical trials are research studies that test new treatments, medications, or procedures to see if they are safe and effective. For people with CGD, participating in a clinical trial may provide access to cutting-edge therapies that are not yet widely available.[7]
To qualify for most CGD clinical trials, patients must have a confirmed diagnosis of chronic granulomatous disease. This confirmation typically requires documented results from neutrophil function tests, such as the DHR test, showing that the patient’s white blood cells are not producing the necessary chemicals to fight infections. The DHR test result serves as objective proof that the immune system has the specific defect characteristic of CGD.[9][21]
Genetic testing results are also crucial for clinical trial qualification. Many trials specify which type of CGD they are studying, whether X-linked or autosomal recessive, and which specific gene mutation is involved. Researchers need this information to ensure that the trial includes patients who will most likely benefit from the experimental treatment being tested. For example, some gene therapy trials may only accept patients with mutations in a specific gene like CYBB.[3][9]
Blood tests are standard requirements for clinical trial screening. These tests assess overall health, check for active infections, and evaluate liver and kidney function. Because many experimental treatments can affect these organs, researchers need baseline measurements to monitor any changes during the trial. Blood tests also measure the number and types of blood cells, which is important because CGD and its treatments can affect bone marrow function.[2][13]
Medical history documentation is essential for clinical trial enrollment. Researchers review records of past infections, hospitalizations, and current medications to understand the severity of your disease and how well existing treatments are working. This information helps determine whether you meet the trial’s inclusion criteria, which are the specific characteristics that participants must have. For instance, some trials may require patients to have had a certain number of severe infections within the past year.[1][2]
Imaging studies may be required to assess the presence and extent of granulomas or organ damage. CT scans, MRIs, or ultrasounds can show whether inflammation or infection has affected your lungs, liver, spleen, or other organs. Some clinical trials may exclude patients with severe organ damage, while others specifically focus on treating complications like granulomas or inflammatory bowel disease associated with CGD.[2][5]
Age can be a factor in clinical trial eligibility. Some trials focus specifically on children, while others are designed for adults. The diagnostic criteria remain the same, but age-specific measurements and assessments may be used to evaluate disease severity and overall health. For example, growth patterns in children with CGD may be monitored, as the disease can sometimes affect normal growth and development.[2][7]
Screening for complications related to CGD is often part of clinical trial qualification. Researchers may assess whether you have developed inflammatory bowel disease, which affects many people with CGD, or whether you have autoimmune conditions. Understanding the full picture of your health helps researchers determine if the experimental treatment is appropriate for you and whether you might be at higher risk for side effects.[2][13]
Some clinical trials test treatments like stem cell transplantation or gene therapy, which aim to cure CGD by correcting the underlying genetic defect. For these trials, additional compatibility testing may be required, such as tissue typing to find a suitable donor for stem cell transplantation. These advanced therapies require careful patient selection because they involve significant risks and benefits that must be weighed carefully.[9][21]
