The Strangest, Rarest Diseases in the World

The human body is an incredibly complex machine, and when these “machines” fail, they do so in remarkably complex and strange ways that often remain unexplained by science…

Exploding Head Syndrome

This syndrome affects thousands of people worldwide, characterized by the sensation of one’s head exploding while falling asleep, with no prior warning signs. Most patients with this syndrome are over 50 years old, but it can also occur in teenagers.

Necrotizing Fasciitis

Also known as flesh-eating disease, it is a rare condition caused by certain bacteria, including Group A Streptococcus. This disease is characterized by rapidly progressing cellulitis that can be fatal within 24 hours, with a mortality rate exceeding 70%.

Menkes Disease

This disease is linked to genetic abnormalities and is more common in males than females. A deficiency of copper in the body leads to symptoms such as blurred vision, muscle weakness, and seizures. Treatment primarily involves copper supplementation along with other supportive measures.

Cotard Delusion

This is a type of delusion where the affected individual feels as though they are dead. Many people suffer from Cotard’s syndrome, which can be treated with medication or blood filtering to remove the factor 9-Carboxymethoxymethylguanine (CMMG).

Epidermodysplasia Verruciformis

This condition is caused by a virus from the Human Papillomavirus (HPV) family. The lesions appear as warty, tree-like growths on the face or extremities. While the disease is not fatal, it significantly affects aesthetics and hampers daily activities. Currently, there is no specific treatment other than surgically removing the “branches” when they grow too long and rapidly.

Fibrodysplasia Ossificans Progressiva (Stone Man Syndrome)

A genetic mutation leads to widespread fibrous tissue ossification, resulting in the body becoming rigid and distorted like a living statue. There is currently no effective treatment for this condition.

Polydactylism

Individuals with polydactylism have more than ten fingers or toes, where the extra digits often lack bones and consist only of soft tissue (skin, muscle, connective tissue). On average, one in every 500 newborns has this deformity. The treatment is simple: surgical removal of the extra digits.

Argyria

This condition is caused by prolonged exposure to chemical compounds containing silver, resulting in the skin turning blue or gray. Treatment involves laser therapy, and the condition can be fatal in some cases.

Proteus Syndrome

Also known as Wiedemann syndrome, it is characterized by overgrowth of skin and bony structures, leading to abnormal shapes of the hands and feet. Current treatment methods are still under research.

Werewolf Syndrome

Due to genetic abnormalities, this condition causes uncontrolled hair growth, resulting in excessive body hair or hair in specific areas such as the face, arms, and back. It is extremely rare, with only about 50 cases recorded worldwide.

Porphyria

Porphyria is a condition caused by genetic or acquired factors characterized by disorders in the production of porphyrins and heme chains in red blood cells. Common symptoms include abdominal pain, vomiting, and neurological disturbances.

Alice in Wonderland Syndrome

Hallucinations, disorientation, loss of body sense, and experiencing whimsical phenomena are the main symptoms of this syndrome. It is often seen in children and adolescents and may resolve on its own without special treatment. In some cases, it is associated with the use of hallucinogenic or stimulant drugs such as amphetamines.

Lion Face Syndrome

This condition involves uncontrolled growth of the skull and facial bones, giving the patient a lion-like appearance. A common accompanying disorder is loss of vision due to pressure on the optic nerve from the bone.

Progeria

Progeria, also known as Hutchinson-Gilford progeria syndrome, is a rare disease characterized by accelerated aging. Currently, there are only about 80 known cases worldwide.

Hailey-Hailey Disease

This condition appears after puberty and is characterized by skin lesions that resemble blisters and allergic inflammation. There is currently no specific treatment.

Cronkhite-Canada Syndrome

This is a rare syndrome characterized by symptoms such as loss of taste, intestinal polyps, hair loss, and nail disorders. Approximately 500 cases of this syndrome have been recorded.

Alien Hand Syndrome

Also known as “alien hand syndrome,” individuals with this condition feel that they cannot control their hand, which behaves as if it is not theirs, resulting in purposeless and involuntary actions.

Lymphatic Filariasis

Elephantiasis is notorious for horrifying images of people with swollen, massive limbs resembling those of elephants. Currently, around 120 million people worldwide are infected with lymphatic filariasis, with 40 million experiencing severe symptoms.

This disease is caused by parasitic worms transmitted through mosquitoes; symptoms may not appear for many years after infection. Once infected, the larvae live in the blood, reproducing and spreading over many years.

When the parasites accumulate significantly in blood vessels, they obstruct circulation, leading to fluid accumulation in surrounding tissues, resulting in swelling in common areas such as arms, legs, and breasts.

Parry-Romberg Syndrome

This syndrome, of unknown origin, is primarily characterized by the atrophy of muscle and skin on one side of the patient’s face, causing asymmetry and aesthetic issues. Currently, there is no effective treatment.

Lamprey Disease

This is perhaps the most frightening condition due to visible lesions on the body, particularly around the eyes, resembling yellow spines or the mouth of a lamprey fish with razor-like teeth and a deep throat. The cause and treatment of this disease remain unclear.

Early Aging Syndrome

A small error in genetic coding can lead to early aging syndrome, causing a child’s body to rapidly undergo the aging process accompanied by symptoms such as baldness, heart disease, brittle bones, and arthritis. Children born with this condition typically do not live past the age of 13. Early aging syndrome is extremely rare, with only about 48 reported cases worldwide. However, there is one family with as many as five children affected by this disease.

Clinical Lycanthropy

This is a rare psychiatric syndrome where individuals believe that they can transform into or have already transformed into animals. Those suffering from this condition often behave like animals and attempt to reach areas inhabited by wildlife, such as parks and forests.

Apotemnophilia

Patients with this condition are obsessively compelled to amputate healthy limbs or other body parts. It is believed to be related to damage in the right parietal lobe of the brain, but doctors have yet to determine a definitive cause for this syndrome.

Capgras Delusion

This extremely rare syndrome causes patients to believe that those around them, including family members, have been replaced by impostors. Capgras delusion often occurs after a traumatic brain injury or in patients diagnosed with dementia, schizophrenia, or epilepsy.

Stendhal Syndrome

Stendhal syndrome can be simply understood as the shock caused by beauty. Most people experiencing this syndrome will only have temporary symptoms. Those affected will experience rapid heartbeat and feelings of anxiety and confusion after encountering a work of art or anything they perceive as magnificent. The syndrome is named after a 19th-century French author who detailed his overwhelming experience after a trip to Florence in 1817.

Klüver-Bucy Syndrome

This condition involves a compulsion to eat inedible objects. Individuals with this syndrome are often drawn to various objects. It is quite challenging to diagnose, and doctors believe it results from severe trauma to the temporal lobe of the brain.

Factitious Disorder

Those with this disorder have an obsession with not being healthy. Some individuals intentionally make themselves unwell or will feign symptoms and fabricate stories about why they are ill when visiting the doctor.

Sanfilippo Syndrome

At 18 months old, Lydia was diagnosed with Sanfilippo syndrome. (Photo: Dailymail).

Sanfilippo syndrome is one of many rare conditions that can lead to what doctors refer to as childhood dementia.

This rare genetic disorder affects only about 5,000 people in the United States and causes symptoms similar to childhood dementia, including the inability to speak, walk, feed themselves, or remember any skills they have learned throughout their lives.

The condition affects approximately one in every 70,000 births each year and develops when both parents pass on a faulty gene. Most individuals with the condition begin to experience decline around the age of four and do not survive past adolescence.

Those affected by Sanfilippo syndrome lack a specific enzyme that breaks down waste produced in the body, leading to a buildup of toxic substances in their brains.

Signs and symptoms include mild speech delays, hyperactivity, irritability, coarse and excessive hair growth, coarse facial features, severe sleep disturbances, respiratory infections, ear infections, digestive issues, and unsteady walking.

As toxins accumulate in the brain, they can lead to seizures, motor problems, and chronic pain; however, due to behavioral symptoms, Sanfilippo is often misdiagnosed as ADHD or autism.

There are four subtypes of this condition, depending on the type of enzyme that is deficient or defective. Globally, MPS IIIA is the most common type, accounting for over half of the cases and is also considered the most severe, causing symptoms and death at an earlier age.

There is currently no approved treatment for this condition, but research and clinical trials on enzyme replacement therapy are underway, aiming for potential treatments that could slow the progression of the disease and extend patient lifespan.

So far, doctors are exploring ways to manage and treat the symptoms associated with Sanfilippo syndrome.

In June, it was announced that Ultragenyx Pharmaceutical is preparing to submit a gene therapy application for Sanfilippo syndrome by the end of 2024 after working with the FDA for expedited review of this potential treatment.

In an initial trial, the biotech company reported seeing stability or improvement in cognitive function in 16 out of 17 treated participants.

Additionally, a 2023 study found that four out of five patients diagnosed with Sanfilippo continued to achieve cognitive skills comparable to the development of healthy children after being treated with the investigational gene therapy.

It remains unknown how much this therapy will cost, when and how it will be provided, or whether health insurance will cover it.