Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.
About Rare Diseases
A rare disease is one that affects fewer than 200,000 people in the United States. There are nearly 7,000 rare diseases. More than 25 million Americans have one.
- May involve chronic illness, disability, and often premature death
- Often have no treatment or not very effective treatment
- Are frequently not diagnosed correctly
- Are often very complex
- Are often caused by changes in genes
It can be hard to find a specialist who knows how to treat your rare disease. Disease advocacy groups, rare disease organizations, and genetics clinics may help you to find one.
It sits within Genetics/Birth Defects and Symptoms.
When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.
Research on Rare Diseases
1,016 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.
What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.
Research currently under way
- A Real-World Medical Chart Review of Spinal Muscular Atrophy Patients Treated With Onasemnogene Abeparvovec in Saudi ArabiaNovartis Pharmaceuticals
- A Study of SGT-212 Gene Therapy in Friedreich's AtaxiaSolid Biosciences Inc.
- Genetic Analysis of Uncommon Disease Presentations in Non-US PopulationsNational Human Genome Research Institute (NHGRI)
- Caregiving Networks Across Disease Context and the Life CourseNational Human Genome Research Institute (NHGRI)
- Vascular Disease Discovery ProtocolNational Heart, Lung, and Blood Institute (NHLBI)
- Testing the Effectiveness of Two Immunotherapy Drugs (Nivolumab and Ipilimumab) With One Anti-cancer Targeted Drug (Cabozantinib) for Rare Genitourinary TumorsNational Cancer Institute (NCI)
Research already completed
- BV-CHEP Chemotherapy for Adult T-cell Leukemia or LymphomaUNC Lineberger Comprehensive Cancer Center
- Rare CNS Tumors Outcomes &RiskNational Cancer Institute (NCI)
- Cross-sectional Characterization of Idiopathic BronchiectasisNational Heart, Lung, and Blood Institute (NHLBI)
Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.
Where to read more
Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.
Learn More
- Frequently Asked Questions about Rare DiseasesNational Human Genome Research Institute
- Genetic and Rare Diseases Information CenterGenetic and Rare Diseases Information Center
- Genetics: MedlinePlus GeneticsNational Library of Medicine
- Human Genome Project (HGP)National Human Genome Research Institute
- Rare Diseases at FDAFood and Drug Administration
- Undiagnosed Condition in a Child FAQNational Human Genome Research Institute
- Undiagnosed Condition in an Adult FAQNational Human Genome Research Institute
Clinical Trials
- ClinicalTrials.gov: Rare DiseasesNational Institutes of Health
Medical subject headings
Clinicians and researchers index this subject under Rare Diseases. These are the terms to use when searching medical literature.
This page is built from the MedlinePlus health topic record for Rare Diseases, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.