There are approximately 7,000 rare diseases – defined by the National Institutes of Health (NIH) as conditions that affect 200,000 people or fewer. Some you’ve probably heard of — such as spina bifida, cystic fibrosis, or Tourette syndrome — but the rest can be more obscure. Most are caused by a genetic mutation or defect, and the majority affect children and have no cure. Here are 10 facts everyone should know about rare diseases.

  1. Rare diseases affect nearly 30 million Americans combined. When you take into account the total number of people living with a rare disease in the United States, they don’t sound so rare. For perspective, consider that in 2014, there were 14.5 million Americans with a history of cancer, according to the American Cancer Society. And 1.5 million Americans have a stroke or heart attack each year. Rare diseases, by comparison, impact many more people.
  2. It can take several years to diagnose a rare disease. Many rare diseases have nonspecific symptoms such as pain, weakness, and dizziness, which can make them hard to diagnose. They can also be hard to diagnose because they’re so unusual. Your doctor may never have seen a similar case and may not even realize a specific disease exists. In addition, it could take weeks or months for you to get an appointment with a specialist. Then, if that specialist was not the right one, you might wait months before seeing the next one. Patients with rare diseases visit more than seven doctors on average before receiving an accurate diagnosis, according to a 2013 study published in the Journal of Rare Disorders. While it’s certainly frustrating, it’s important that you don’t give up searching for an accurate diagnosis, whether you suspect a rare disease or something more common. Continue to see your primary care physician, who can help track your symptoms and let you know if any new research has been done that might help.
  3. Only 5 percent of rare diseases have treatments. Drug research that helps a limited number of people can be cost-prohibitive for pharmaceutical companies. (Remember, the pool of prospective patients with a rare condition is by definition less than 200,000, compared to the pool of those who could potentially take cholesterol-lowering drugs, for example.) In response, the Food and Drug Administration (FDA) created the Office of Orphan Products Development (OOPD) in 1983 to offer grants and other incentives to pharmaceutical companies for research.
  4. Genetic testing can help diagnose many rare diseases, but not all. Genetic testing identifies a genetic cause in an estimated 25 percent to 30 percent of cases. As mentioned above, even with a diagnosis, it’s still unlikely that there is a cure or even treatment for any given rare disease. However, one major benefit of getting a definitive diagnosis of a rare disease is peace of mind. You also may have an easier time getting insurance to cover doctor bills, procedures, and tests once a condition has been diagnosed.
  5. Newborn screening for rare diseases is recommended. Screening requirements for newborns vary by state, but they’re increasingly becoming routine, especially for cystic fibrosis, sickle cell disease, and other conditions where early detection and treatment can improve outcomes for the child. Even without a cure for a particular condition, early diagnosis is important to prevent death or disability and to help children reach their full potential.
  6. Prenatal testing for rare diseases is becoming more advanced. It’s now possible to test early in a woman’s pregnancy for a handful of rare diseases, including Trisomy 18 syndrome, also known as Edward’s syndrome, and Trisomy 13, also known as Patau syndrome. The procedure is a simple blood test that can be performed as early as the 10th week of pregnancy. More prenatal screening for other rare diseases is on the horizon.
  7. Some cancers are rare diseases. There are cancers that happen so infrequently they fall under the rare-disease threshold. Examples include tongue cancer (about 39,500 people will get oral cavity or oropharyngeal cancer in 2015), thyroid cancer (about 62,000 cases were diagnosed in 2014), and testicular cancer (8,430 new cases of testicular cancer will be diagnosed in 2015), according to the American Cancer Society.
  8. Having a rare disease can be costly. Between visits to numerous specialists, traveling hundreds of miles to specialty centers, and paying for tests and procedures that may not be covered by insurance, the costs associated with a rare disease can be debilitating. There are, however, numerous groups that can help with the costs. The National Organization for Rare Diseases has a patient assistance program, and Rare Disease United lists other organizations and websites for resources.
  9. Finding a support group is important. A rare disease can be isolating for the patient as well as for the caregiver, especially when it’s your child who has the disease. Connecting with others can be essential, not only for support, but also to share information and resources. Find a support group through the National Organization for Rare Diseases.
  10. Rare Disease Day is on Leap Day. Fitting for rare diseases, the national awareness day is on February 29, a date that’s only on the calendar every four years. (It’s moved to February 28 on non-leap years.) The day was started by the European Organisation for Rare Diseases and is now recognized globally. The symbol for rare disease awareness is a zebra-striped ribbon.