Unsolved medical mysteries that still baffle scientists

By Alistair Gardiner
Published November 8, 2021

Key Takeaways

Medicine is characterized by rapid advancements. Just think: 25 years ago, HIV was all but a death sentence, and 75 years ago, we were still practicing lobotomies. Despite this progress, there are still many conditions and cases that leave medical experts scratching their heads. Here are five of the most baffling medical mysteries ever reported, all of which remain unsolved.

Mermaid syndrome (sirenomelia)

Mermaid syndrome is a multi-system congenital deformity that is rare and lethal, characterized by the fusion of the lower limbs, which makes them appear like a mermaid’s tail. According to a case study published in the Journal of Medical Case Reports in April, sirenomelia occurs in roughly one of every 60,000-70,000 pregnancies and is associated with urogenital and gastrointestinal malformations.

Authors note that the etiology of the condition remains unknown, but there are two hypotheses about how it arises. Some believe that sirenomelia is the result of defective blastogenesis, which leads to impairment in the formation of caudal structures. Others believe the condition develops due to abnormal vasculature patterns, based on the fact that in most cases of sirenomelia, fetuses only have one umbilical artery, as opposed to the typical two. However, most of the mechanisms involved remain unclear.

Researchers have pinpointed some risk factors, which include maternal diabetes and exposure to heavy metals. There also may be a genetic factor, but confirmation requires additional research. For now, mermaid syndrome retains its status as a major medical mystery.

Highly superior autobiographical memory

Those with highly superior autobiographical memory (HSAM) are the closest real-life examples of having “photographic memory.” HSAM patients can recall almost anything from their lives in meticulous detail, from events they’ve witnessed to conversations they’ve had. Jill Price received the first official diagnosis of HSAM in 2006. According to an article published in Reader’s Digest, if you gave her a date, she was able to tell you exactly what day of the week it fell on.

As noted by the authors of a study published in Brain Connectivity in May, the neural mechanisms of HSAM are still not understood. The research aimed to explore the neurobiology of the condition, using functional magnetic resonance imaging to examine the brain of a 20-year-old with HSAM, along with the brains of 16 individuals with normal autobiographical memory. They found that HSAM is “associated with increased expression of neural pathways that support memory encoding, retrieval, and elaboration, but also with reduced expression of patterns typically involved in information control and metacognition.” However, the study didn’t explain why or how certain people develop the condition.

Stiff person syndrome

According to information from the National Institute of Neurological Disorders and Stroke, patients with stiff person syndrome (SPS) experience random shifts in muscle rigidity in the trunks and limbs, as well as a highly increased sensitivity to noises, emotional distress, and other stimuli, which can provoke muscle spasms. Patients with SPS often end up functionally disabled or borderline paralyzed, and many stay home because unexpected outside noises can prompt spasms. 

While researchers have established that SPS affects twice as many women as men, and is commonly associated with autoimmune diseases (like diabetes or thyroiditis), the causes of the condition remain unknown. Researchers hypothesize that SPS is related to dysfunctional autoimmune responses in the brain and spine.

According to information provided by the Cleveland Clinic, roughly one in a million people will develop SPS. Authors also note that patients with SPS tend to produce antibodies that attack glutamic acid decarboxylase (GAD), an enzyme that helps make neurotransmitters called gamma-aminobutyric acid (GABA), which are involved in controlling muscle movement. However, not all SPS patients present with these antibodies, leaving the exact causes of SPS a mystery.

Morgellons disease

Morgellons disease sounds like something straight out of a body-horror film. Patients report feelings of something crawling on or stinging their skin, and the condition is characterized by the emergence of small fibers or other particles from patients’ sores.

According to information provided by the Mayo Clinic, other symptoms can include fatigue, difficulty concentrating, short-term memory loss, and depressed moods. Some physicians believe the condition is based on delusions and may treat it with cognitive behavioral therapy, antidepressants, antipsychotic drugs, and counseling. Likewise, after conducting a study with 115 patients with Morgellons, the CDC found that most of the fibers were made of cotton. The agency concluded that it “isn't caused by an infection or parasites” and has “an unexplained dermatopathy.” 

On the other hand, some research has found possible links between Morgellons and infection with Borrelia spirochetes. Further research is required to establish a firm cause for the condition. 

Syndrome X

Perhaps the greatest medical mystery of all time, Syndrome X was the name given to a condition in which a child doesn’t age properly. The first recorded case was that of Brooke Greenberg, who died in 2013 at the age of 20. Doctors were baffled by Greenberg, whose body had stopped developing at age of 5. Tests showed that there were no abnormalities in her genes associated with aging.

An article published in Aging in 2015 described five other cases that appeared similar to Syndrome X, all of which involved children who resembled toddlers while aging into adulthood. Researchers performed various tests but failed to detect any genetic causes, and, using the epigenetic clock method, found that the rate of development in blood and some other tissues was normal. As of yet, many fundamental questions about the condition remain unanswered.

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