Most rare and unusual diseases in the world

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(ORDO NEWS) — Throughout history, mankind has struggled with disease. Plague, smallpox, cholera, cancer, influenza, tuberculosis – the number and variety of dangerous diseases is amazing.

Nearly 10 million people die of cancer each year (as of 2020), while the number of deaths from influenza and respiratory diseases is at least 650 thousand per year. Fortunately, timely diagnosis and treatment saves many lives through disease awareness.

But what about rare diseases? It is estimated that patients with unknown diseases make up to 10% of the population, but it is impossible to say exactly how many.

Moreover, some diseases occur in different demographic groups or regions. But it is one thing to know what is happening to you, and quite another to be ignorant throughout your life. So,

Most rare diseases are genetic and many of them appear at an early age.

Case history of Debbie Schwartz

If the character Hugh Laurie on House M.D. actually existed, would he be able to diagnose an unknown disease in an attempt to save a patient’s life? I would like to believe that yes, however, in reality everything is different.

This is confirmed by the story of 47-year-old Debbie Schwartz, whose life is spent in obscurity due to a mysterious disease that still does not even have a name.

Debbie, 47, spent most of her life surrounded by doctors, feeling hopeless, isolated and humiliated. The specialists could not identify the disease, which is why they opened the first private clinic for patients with nameless syndromes.

Debbie was one of the clinic’s first patients and hopes to finally get a diagnosis. But what exactly is happening to her?

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For most of her life, Debbie Schwartz struggled with a rare disease that has no name

According to BBC News, health problems arose when Debbie was 11 years old. According to the woman, at first doctors treated her problems with disdain, and in her late teens her vision, speech, hearing and mobility deteriorated.

As an adult, Schwartz lost her sight and hearing, experienced balance problems, and lost sensation in her hands and knees, the article says.

In 2005, doctors were partially able to establish a possible cause of what was happening, suggesting the development of a mitochondrial disease, a group of hereditary conditions caused by defects in key parts of the body’s cells (by 2021, scientists were able to identify about 350 genes responsible for such diseases.

Later, Debbie was diagnosed with three more “very rare disorders” (neurological and motor in nature). Today, a woman cannot do without nurses who come to her three times a day. However, a serious illness did not prevent Schwartz from obtaining a degree in biochemistry and becoming a science teacher.

Diagnosis of rare diseases

Today, rare diseases include more than 7,000 different conditions that collectively affect more than 350 million people worldwide.

Diagnosis and treatment of such diseases is difficult, since the symptoms may coincide with those of common diseases, and the options for their treatment are limited. However, due to the development of genome sequencing technology in the future, the situation should change.

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Modern methods of diagnosing genetic diseases will help scientists invent drugs for a variety of diseases

Next generation sequencing (NGS) is a group of methods for determining the nucleotide sequence of DNA and RNA. Recall that NGS technologies have revolutionized genomic research over the past two decades: today it is possible to sequence a patient’s genome in a day, while in the past this process took weeks.

A rare disease or disorder is any disease that affects less than 200,000 people, which is actually quite a lot and covers thousands of different conditions.

However, the use of NGS technologies is fraught with a number of difficulties – symptoms appear infrequently, and doctors lack experience in diagnosing such diseases due to their low prevalence. As a result, treatment options are limited, even though rare diseases represent a major global health problem.

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Genetic diseases are a major global health problem and are often untreatable

To effectively diagnose and treat patients with rare diseases, it is necessary to agree on a definition of the unique combination of genetic, phenotypic and environmental traits associated with each unknown and rare disease, writes the authors of a paper published in the National Library of Medicine.

The rarest diseases in the world

Since there is no single list of rare diseases, researchers identify several of the most common conditions in the world.

Note that smallpox and poliomyelitis, which were defeated by vaccination, are deliberately excluded from this list (for this reason, these diseases are rare today). You can read more about how vaccines work and why the scientific community is calling for their active use here.

Hutchinson-Gilford Syndrome (Progeria)

Progeria, or accelerated aging syndrome, affects about one in every eight million children. This rare genetic mutation manifests itself at an early age and is the cause of premature death. At the moment, 100 cases of this unusual disease have been described in the world literature.

Researchers believe that the cause of the development of Hutchinson-Gilford syndrome is a sporadic mutation of the LMNA gene, which encodes a protein that provides molecular support for cell nuclei.

Children with progeria tend to have large heads, limited range of motion, and arteriosclerosis in the brain (which increases the chance of a heart attack or stroke).

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At 18, Ashanti Smith looked like a very old woman

Progeria is often referred to as “Benjamin Button’s disease” and few patients live beyond their 20s. In 2021, the media reported the death of 18-year-old Ashanti Smith, who, although she looked like a very old person, generally lived the most ordinary and normal life. The girl died as a result of heart failure.

Kuru – the disease of cannibals

In a previous article, we talked about an extremely rare fatal disease that killed mainly women and children in the tribes of Papua New Guinea.

As it turned out, the cause of the mysterious illness was a ritual funeral process – the brain of a deceased comrade was removed from the skull, cooked and eaten. Women and children fell ill more often than men, since the brain was considered a healthy delicacy.

Kuru is caused by prions, abnormally shaped proteins that cause mad cow disease (Creutzfeldt-Jakob disease) and Gerstmann-Stressler-Scheinker disease (GSS). Prions are also pathogens in a wide range of other animals, such as deer and cattle.

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Kuru is a prion disease that occurs very rarely, if at all, today

Scientific analysis of the brains of people who died of mad cow disease or kuru showed that their brain tissue had a spongy appearance. That is, where there should have been cells, there were holes indicating encephalopathy, or a decrease in the number of brain cells.

These infectious agents are transmitted both by eating contaminated meat and by direct infection to the brain, skin, and muscle tissue. Today, cannibalism is outlawed and this disease practically does not exist, which is good news.


According to the available data, the clinical manifestations and severity of methemoglobinemia are characterized by cyanosis of the skin (observed mainly at a low level of a type of hemoglobin that is transformed into an iron carrier in human blood.

Most of us have less than 1% methemoglobin in our blood, while patients with a rare disease have 10% to 20% of it in their blood, experts say.

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Hereditary enzymopenic methemoglobinemia is characterized by cyanosis

Because iron-containing hemoglobin carries only a reduced amount of oxygen, patients with methemoglobinemia are at a higher risk of developing heart abnormalities that lead to premature death.

Among the symptoms of the disease are increasing weakness, malaise, shortness of breath during physical exertion, irritability, headache and dizziness. Mortality from methemoglobinemia is at least 70%, and the disease itself is inherited.

Fields disease

The fourth disease on our list is characterized by dysfunction of the muscular system. This progressive disease causes extremely painful muscle spasms that occur up to 100 times a day. The disease is still a mystery to doctors and gained notoriety after sisters Kirsty and Katherine Fields fell ill at the age of four.

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Fields disease is so rare, two cases have been found in history with a similar diagnosis. Both patients were from the same family

By the age of 9, both girls could hardly move, by 11 they could not eat on their own, and at the age of 14 they lost the ability to speak, old from severe bouts of pain.

As experts found out, Fields disease affects the nervous system, contributing to the slow death of nerve cells and can manifest itself at any age. The twins are 26 today.

Alice in Wonderland Syndrome

Closes the list of rare diseases is the so-called Alice in Wonderland syndrome (AIWL), which was discovered in 1955.

This name was given to the syndrome by the British psychiatrist John Todd, since the symptoms of the disease reminded him of the changes in the body that occur with the main character of the famous novel by Lewis Carroll.

The most noticeable and disturbing symptom is a change in body image, when the patient does not understand its size and shape – usually this concerns the hands and head.

Distortion of visual perception is considered the next symptom, in which the patient “sees” objects of the wrong size or shape.

This means that everything around seems smaller or larger than it actually is. Such patients are also unable to perceive distance normally (for example, a small corridor may appear very long and vice versa).

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Frame from the cartoon “Alice in Wonderland”. Falling down a rabbit hole resembles symptoms of an unusual illness

Other symptoms include distorted perception of time, sound, and touch. So, some patients lose the ground under their feet and cannot identify objects by touch. There is no cure for AIWS, and researchers cannot figure out what exactly is causing the disease.

Most often, Alice in Wonderland syndrome affects children and adolescents, and, fortunately, passes as they grow older.

However, cases of AIWS in adults are known, and brain tumors, migraine, epilepsy, and encephalitis are among the probable causes. Experts note that this syndrome is not fatal and you have not been fully studied.

What’s good about rare diseases?

Thanks to scientific and technological progress, researchers have managed to discover a lot of strange and deadly diseases.

Moreover, in recent years, there have been more such findings, and their occurrence and prevalence depend on the location and many different factors, which, of course, complicates diagnosis and treatment methods.

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Studying rare and unusual diseases can be useful

The diseases described above, however, can benefit humanity by facilitating the development of new drugs and further medical progress.

Ultimately, there are many diseases unknown to science, which we will be able to learn about in the coming decades. Let’s hope that in the future, experts will be able to treat and prevent a wide variety of diseases.


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