The woman unable to feel FEAR due to rare genetic condition

Most of us would tremble when faced with a venomous spider or a dangerously high cliff edge. But one woman has a rare disease meaning she is biologically unable to feel fear. The U.S. woman, known to doctors as SM, has been put into life-threatening situations but remains completely unfazed.

She didn’t panic at being held at gunpoint and knifepoint – and didn’t even call the police after these attacks. She was also nearly beaten to death by her first husband, but never felt scared. When faced with snakes that could be poisonous to her, she is so curious she has to be restrained from touching them.

SM has a rare genetic condition called Urbach-Wiethe disease, which causes parts of her brain to harden and waste away, NPR reports.

Urbach-Wiethe disease has three main symptoms: people with the condition have a hoarse voice, small bumps around their eyes and calcium deposits in the brain.

These deposits cause parts of the brain to calcify and harden, which can lead to epilepsy or other abnormalities.

In SM’s case, almond-like structures called amygdala found deep in the brain have calcified and wasted away.

The amygdalae are crucial to the human fear response, and so SM is now literally unable to feel the emotion fear.

Normally, in situations that might cause danger, the amygdalae would send signals to the body that would induce symptoms of fear: the heart to start racing and the palms to sweat.

But for SM, as this bit of her brain doesn’t exist, she doesn’t experience these symptoms in situations others would find scary.

She is also unable to recognise a fearful facial expression on another person.

Doctors note this is an isolated defect: she has normal intelligence and feels other emotions such as joy, sadness, anger in the same way as others.

Scientists have identified only about 400 people worldwide with Urbach-Wiethe disease.

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