Remember the “Ice Bucket Challenge” from a few years ago? Thanks to this celebrity-fueled craze, this "rare disease" was shoved under the public's eye and received $115 million dollars in funding donations in just 30 days, helping provide a major genetic breakthrough towards understanding the disease.

Today is Rare Disease Day – an annual call to arms to raise awareness of the 7,000-odd “rare diseases” that affect millions of people each day.

In the US, a disease is defined as rare if it affects fewer than 200,000 Americans at any given time. In Europe, a disease is defined as rare when it affects fewer than one in 2,000. So while the term “rare disease” might suggest otherwise, there are around 350 million people out there living with one of these rare diseases. Many more perhaps go undiagnosed or misdiagnosed.

The problem lies in awareness, diagnosis, funding, and research. Rare diseases and disorders are less likely to receive the funding and awareness required to accelerate research. 

While the more prevalent diseases such as cancer, heart disease, and stroke understandably take precedence in science’s “things to do list”, it’s crucial these millions of people with rarer diseases don’t get left behind.

But while there’s a lot of work to be done, the past few years have shown progress when it comes to rare disease research. In 2015, 47 percent of novel new drug approvals were for rare diseases, and 566 medicines are in development for patients with rare diseases.

Here’s just a handful of rare diseases that with a little more attention, funding, and research could improve the lives of many. From the fascinating to the well-known success stories, all of these diseases can be found in the Orphanet Report Series (PDF) on rare diseases in 2016.

Fibrodysplasia ossificans progressiva, aka “Stone Man Syndrome”

“Stone Man Syndrome” (image right) is a genetic disorder that turns soft tissues, like muscle tissue and connective tissue, into bone. Eventually, movement becomes severely constrained and bone begins to grow on the outside of the body. Only a few hundred cases have been reported and there is little in the way of medical treatment.

^{Image of a skeleton with Fibrodysplasia ossificans progressiva. Joh-co/Wikimedia Commons CC BY-SA 3.0}

Böök syndrome

This condition is characterized by a lack of premolar teeth, excessively sweaty hands, and a premature graying of the hair. Originally described by Swedish geneticist Jan Jarvid Böök in the 1950s, just 26 published cases of this disease have been reported.

Chronic hiccup

This rare disease is pretty much what it sounds like – hiccups that last for extended periods of time, ranging from weeks to years to decades. The longest documented episode lasted 60 years. As strange as it may seem, this debilitating illness affects up to one out of every 100,000 people.

Multiple Myeloma

Multiple Myeloma is another success story of increased awareness and research. Thanks to the improvement of two first-class medicines approved in 2015, the severity of this rare form of bone marrow cancer has taken a beating. This form of cancer occurs in plasma cells, a type of white blood cell that's normally responsible for producing antibodies. New treatments help activate the immune system to attack the cancerous cells and reduce the size of tumors.

Cystic fibrosis

Cystic fibrosis might be one of the best known rare diseases. These individuals experience a buildup of thick, sticky mucus in the lungs, digestive system, and other organs. As one of the “big names” of the rare disease lexicon, treatment of this disease has grown a huge amount over the past decades.

Bird headed-dwarfism, Montreal type

There are only three published cases of this disease, which is characterized by a low birth weight, small head, narrow pointed face, a beak-like nose, large eyes, and intellectual disability.

Epidermodysplasia verruciformis, aka “Tree Man syndrome”

A few months ago, Abul Bajandar from Bangladesh (below) became the first person to have been potentially cured of Epidermodysplasia verruciformis. This hereditary condition is characterized by an extreme susceptibility to HPV, the human papillomaviruses, causing an uncontrollable outburst of scaly warts to grow on the person’s body, often said to resemble tree bark.

^{Abul Bajandar, one of the most famous cases of Epidermodysplasia verruciformis. Monirul Alam/Wikimedia Commons CC BY-SA 4.0}