What is a Rare Disease?
A rare disease is defined as any disease which affects a very small percentage of people in a population. Most rare diseases are genetic, and symptoms do not appear immediately but are present throughout a person's entire life. About 30% of children with rare diseases die before reaching their fifth birthday. More than 300 million people worldwide are living with a rare disease.
The US Rare Diseases Act of 2002 defines a rare disease as a condition that affects less than 200,000 people in the United States or about 1 in 1,500 people. Out of 7,000 known rare disease conditions, 80% are genetic disorders, and 50% of those affected children. A patient will often present symptoms associated with more common conditions, which makes it even more difficult to diagnose. It might also be the case when the physicians are completely unaware of the disease.
The National Institutes of Health (NIH) supports research to improve the health of people with rare diseases. Around 27 Institutes and Centers at the NIH fund medical research for rare diseases. One of these Centers, the National Center for Advancing Translational Sciences (NCATS), focuses on getting new cures and treatments to all patients more quickly. NCATS supports research through collaborative projects to study common themes and causes of related diseases. This approach aims to speed the development of treatments that will eventually serve both rare and common diseases.
Despite technological and medical advances misdiagnosis or a lack of knowledge pose significant challenges for people with a rare disease. Access to support services and therapy can be a huge problem. Often the cost of managing patients with a rare disease and the high price of a medicine is a matter of concern. Therefore, there is a pressing need for collaborative research on a global scale and funding for research to gain a thrust. 
A fundamental challenge in researching rare diseases is gaining access to enough patient data. Patients are difficult to find, and there are privacy issues and data ownership. The drug development process has to be more patient-centric. This approach will not only help patients with rare diseases but those with more common ones as well, leading to significant benefits to payers.
Before the Legislative laws were passed there were no drugs specifically developed to treat rare diseases. But, with the passage of the Orphan Drug Act in the US in 1983, about 2,755 agents have received an orphan drug designation, with 424 orphan drug approvals. The recent success in orphan drug development has resulted in many biotech startups having focused units working on rare diseases. Consequently, increased investment of venture capital companies and early-stage biotech companies in rare disease programs is also on the rise.
Some of the NCAT Programs Areas Are: 
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