Creutzfeldt-Jakob disease (CJD) is as rare as it is devastating. It is rapid, fatal, and notoriously difficult to diagnose. Since 1998, Belgium has been monitoring CJD through a dedicated national surveillance system. In collaboration with Sciensano and UZA, we help doctors across the country reach a clear diagnosis, as the national diagnostic reference center.
November 12th is International CJD Awareness Day, a day when patients, families, healthcare professionals, and researchers around the world draw attention to Creutzfeldt-Jakob disease (CJD). CJD is a rare neurodegenerative disorder that is often rapidly progressing and diagnosed unexpectedly, profoundly affecting the lives of patients and those around them. It is named after German neurologists Hans Gerhard Creutzfeldt and Alfons Maria Jakob, who first described its clinical and pathological features in the 1920s.
How does CJD develop?
CJD is caused by abnormally folded proteins, called prions, which accumulate in the brain and damage neurons. That damage cannot be reversed and leads to severe neurological decline.
The disease often begins with subtle symptoms like memory loss, anxiety, or sudden personality changes. In its early stages, CJD can resemble other conditions such as Alzheimer’s, Parkinson’s, or even psychiatric disorders, but the decline in CJD is much faster. As the disease progresses, patients can quickly develop severe balance and speech problems, uncontrolled muscle movements or dementia, leading to full care dependency in just a few months. Most people with Creutzfeldt-Jakob disease die from complications of the disorder in under a year.
There are several forms of CJD. In most cases, the disease appears out of the blue, usually later in life, with no known cause or family history. A smaller number of cases are inherited and run in families due to a genetic mutation. A third, very rare form was linked to eating beef from cattle infected with “mad cow disease” in the 1990s. Thanks to strict controls, this variant form no longer occurs in Europe.
CJD in Belgium
In Belgium, only a few people are diagnosed with CJD each year, on average 2 to 3 cases per million each year. The numbers may be low, but the impact on patients and their families is not. There is currently no treatment that can slow or stop the disease. Doctors can help reduce symptoms such as muscle stiffness or anxiety, but the focus of care is comfort and support for both patients and their caretakers.
That is why a correct diagnosis is crucial. The sooner doctors have clarity, the sooner they can provide the right care. That’s where the Institute Born-Bunge plays a central role. As the national reference center for CJD in Belgium, we perform the specialized analyses needed to confirm the diagnosis with certainty. When CJD is suspected, doctors send us cerebrospinal fluid or tissue samples for testing. No single test is enough: it’s always the combination of clinical assessment, brain imaging, and laboratory results that leads to a definitive diagnosis.
One of the most important tools in confirming CJD today is RT-QuIC, or Real-Time Quaking-Induced Conversion. This highly sensitive test detects tiny amounts of misfolded prion protein—the hallmark of CJD—in a patient’s cerebrospinal fluid (CSF). In the lab, normal prion protein is added to the sample along with a dye that lights up when misfolding occurs. Through cycles of gentle shaking, any disease-associated prions in the sample trigger a chain reaction of misfolding, which is tracked in real time. A positive signal strongly supports the diagnosis. When combined with other biomarkers like 14-3-3 or tau, and clinical or imaging data, RT-QuIC provides a powerful, non-invasive tool for early and accurate CJD diagnosis.
To diagnose Creutzfeldt-Jakob disease (CJD), clinicians use a combination of cerebrospinal fluid (CSF) biomarkers—14-3-3 protein, total tau (t-Tau), and the highly specific RT-QuIC test. While 14-3-3 and t-Tau indicate general brain cell damage and offer supportive evidence, RT-QuIC detects misfolded prion proteins and is currently the most accurate pre-mortem test for confirming CJD. Used together with clinical assessments, MRI, and EEG, these tests help distinguish CJD from other dementias and improve diagnostic certainty.
Why awareness matters
CJD is rare, but never insignificant. The disease progresses quickly, often catches families off guard, and leaves little time to prepare. Early recognition of symptoms, access to reliable testing, and good communication between caregivers and families can make a meaningful difference, even in the absence of a current cure.
That’s why continued awareness, research, and collaboration are essential. Through international networks like Euro-CJD, we work closely with colleagues across Europe to improve diagnostic tools, monitor trends, and advance scientific understanding. Together, we’re building a stronger foundation of knowledge and care for everyone affected by CJD.
