The Rare Disease That Erases Fear: How Some People Live Without It

Published: 25 September 2025. The English Chronicle Desk

Fear is a fundamental survival mechanism, deeply rooted in human evolution. It alerts us to danger, triggers the fight-or-flight response, and keeps us alive. Yet, for a very small number of people, fear is a sensation they never experience. How do these individuals navigate a world designed around caution and risk?

Jordy Cernik, a British man, offers a remarkable example. He had his adrenal glands removed to reduce anxiety caused by Cushing’s syndrome, a rare condition in which the adrenal glands produce excessive amounts of cortisol, a stress hormone. While the surgery alleviated his anxiety, it also produced an unexpected consequence. In 2012, during a trip to Disneyland, Cernik rode a rollercoaster and realized he felt absolutely no fear. Since then, he has skydived from airplanes, zip-wired across Newcastle’s Tyne Bridge, and abseiled down the Shard in London—all without the slightest surge of adrenaline or racing heartbeat.

Cernik’s case is extraordinary, but he is not entirely unique. Individuals with Urbach-Wiethe disease, also known as lipoid proteinosis, display a similar absence of fear. This genetic condition is so rare that only around 400 people worldwide have ever been diagnosed.

One famous Urbach-Wiethe patient, identified as “SM,” has been the subject of extensive scientific research at the University of Iowa since the mid-1980s. In the early 2000s, graduate student Justin Feinstein joined the research team, aiming to understand how to elicit fear in SM.

“We exposed her to every horror movie we could find,” Feinstein, now a clinical neuropsychologist, explains. Yet, films such as The Blair Witch Project, Arachnophobia, The Shining, and Silence of the Lambs failed to provoke any fear. Even visits to the famously haunted Waverley Hills Sanatorium left her unfazed.

The researchers then introduced SM to real-life threats, such as snakes and spiders. Again, she displayed no fear. In fact, she approached and interacted with the animals, driven by a profound curiosity rather than avoidance.

Urbach-Wiethe disease is caused by a mutation in the ECM1 gene on chromosome 1. ECM1 is crucial for maintaining the extracellular matrix, a network that supports cells and tissues. When ECM1 is damaged, calcium and collagen accumulate, causing cell death. The amygdala, an almond-shaped brain region critical to processing fear, appears particularly vulnerable to this process.

Feinstein notes, “What is remarkable is that the fear deficit is highly specific—her ability to experience other emotions, such as happiness, anger, or sadness, remains largely intact.”

The story, however, is more nuanced. The amygdala’s role in fear varies depending on the type of threat. It is particularly important for fear conditioning—a learned response to stimuli associated with danger. Experiments with rodents have shown that if a noise is paired with an electric shock, the animals later freeze when the noise occurs alone.

SM, however, is incapable of this type of fear conditioning. While she instinctively avoids touching a hot pan, she does not experience a racing heartbeat or adrenaline surge when confronted with stimuli previously associated with pain. She also cannot recognize fearful facial expressions in others, though she can identify joy and sadness.

Despite being highly social and outgoing, her inability to assess danger has placed her at risk. On multiple occasions, she has been threatened at knife and gunpoint. Feinstein explains, “She tends to approach people she should avoid, which has led to significant trouble because she cannot judge trustworthiness reliably.”

In one study, researchers measured the personal space SM preferred when a stranger approached her. She indicated comfort at just 0.34 meters (1.1 feet)—roughly half the distance preferred by control participants. This suggests that the amygdala also plays a role in regulating social responses and maintaining safe interpersonal boundaries.

Interestingly, some types of fear appear independent of the amygdala. In experiments where SM inhaled carbon dioxide—a stimulus that induces panic in many people—she experienced a full-blown panic attack, the most intense fear she had ever felt in her adult life. Two other patients with amygdala damage responded similarly.

Feinstein’s research revealed that the brain has two distinct fear pathways, depending on whether the threat is external or internal. For external threats, such as a burglar, snake, or bear, the amygdala functions like an orchestra conductor, coordinating brain regions and bodily systems to mount a response. It receives information from the sensory areas, signals the hypothalamus, which then instructs the pituitary and adrenal glands to release cortisol and adrenaline into the bloodstream. The result is an increased heart rate, elevated blood pressure, and the classic physiological “fight-or-flight” response.

Internal threats, such as detecting elevated CO2 levels in the blood, are processed differently. The brain interprets high CO2 as a sign of suffocation, sensed by the brainstem, which regulates vital functions like breathing. The amygdala normally modulates this response, damping the panic reaction. Without an amygdala, as in SM, the reaction is exaggerated. The precise reason the amygdala exerts this inhibitory control remains unknown.

This phenomenon highlights how the human brain processes fear in highly specialized ways, and how rare genetic conditions can illuminate the complex interplay between emotion, survival instincts, and social behavior. Individuals like Jordy Cernik and SM provide scientists with a unique window into what it truly means to live without fear, challenging our understanding of one of humanity’s most fundamental emotions.