Explore Rare Diseases

Browse conditions organized by body system. Each entry includes symptoms, prevalence, and information about clinical trials.

Blood & Immune

6

Graves' Disease

Affects about 1 in 200 people; most common in women ages 30-50

Graves' disease is the most common cause of hyperthyroidism, an autoimmune condition where antibodies stimulate the thyr...

Key Symptoms

Rapid or irregularUnexplained weight lossTremors in hands
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IgA Nephropathy

About 1 in 100,000 people per year in the U.S.; significantly more common in Asian and Pacific populations (up to 4x higher)

IgA nephropathy is the most common primary glomerulonephritis worldwide, caused by abnormal IgA1 antibodies depositing i...

Key Symptoms

Blood in theProtein in theFlank or abdominal
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Mastocytosis

1 in 10,000 to 1 in 300,000 (estimates vary widely)

Mastocytosis is a rare hematological disorder characterized by clonal expansion of mast cells in bone marrow, organs, an...

Key Symptoms

Flushing, pruritus (itching),Abdominal pain, diarrhea,Anaphylactic reactions triggered
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Severe Combined Immunodeficiency

1 in 50,000 to 100,000 births

Severe combined immunodeficiency is a rare genetic disorder affecting both T cell and B cell immune function, resulting ...

Key Symptoms

Recurrent, severe infectionsSevere diarrhea andFailure to thrive
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Sickle Cell Disease

About 100,000 Americans with SCD; 1 in 13 African-American births; 1 in 36 Hispanic-American births

Sickle cell disease is an inherited blood disorder where hemoglobin polymerizes under low oxygen, causing red blood cell...

Key Symptoms

Severe pain crisesChronic hemolytic anemiaAcute chest syndrome
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Thalassemia

1 in 100,000 people in the U.S.; higher in Mediterranean and Asian populations

Thalassemia is an inherited blood disorder where reduced or absent production of one type of hemoglobin chain causes sev...

Key Symptoms

Severe anemia andJaundice from hemolysisBone pain and
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Connective Tissue & Musculoskeletal

3

Metabolic & Lysosomal

10

Fabry Disease

1 in 40,000 to 60,000 males; higher in females when accounting for carrier status

Fabry disease is a rare inherited lysosomal storage disorder where a missing enzyme causes fatty substances called globo...

Key Symptoms

Burning pain inDark red toCloudy vision or
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Gaucher Disease

1 in 40,000 to 60,000 in general population; 1 in 850 among Ashkenazi Jewish population

Gaucher disease is a rare inherited lysosomal storage disorder caused by deficiency of the enzyme glucocerebrosidase, re...

Key Symptoms

Severe bone pain,Enlarged spleen andFatigue and anemia
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Homocystinuria

1 in 340,000 births (cystathionine beta-synthase deficiency)

Homocystinuria is a rare inherited metabolic disorder characterized by elevated homocysteine levels in blood and urine. ...

Key Symptoms

Lens dislocation (ectopiaMyopia and astigmatismIntellectual disability if
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Hunter Syndrome

1 in 100,000 to 150,000 males; females with disease are rare

Hunter syndrome is an X-linked lysosomal storage disorder caused by deficiency of iduronate-2-sulfatase enzyme, leading ...

Key Symptoms

Developmental delay andCoarse facial featuresGrowth retardation and
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Maple Syrup Urine Disease

1 in 185,000 births in general population; 1 in 400 in Old Order Mennonite communities

Maple syrup urine disease is a rare inherited metabolic disorder where the body cannot properly break down branched-chai...

Key Symptoms

Characteristic sweet orPoor feeding andDevelopmental delay and
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Niemann-Pick Disease

Type A: 1 in 250,000; Type B: 1 in 100,000 to 150,000; Type C: 1 in 100,000 to 150,000

Niemann-Pick disease is a rare lysosomal storage disorder where the body cannot properly break down cholesterol and othe...

Key Symptoms

Enlarged liver andJaundice in infancyDevelopmental delay and
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Phenylketonuria

1 in 10,000 to 15,000 newborns in the U.S.

Phenylketonuria is an inherited metabolic disorder caused by a missing enzyme that prevents the body from properly break...

Key Symptoms

Light-colored skin andMusty or mousyIntellectual disability if
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Pompe Disease

1 in 40,000 people (infantile form: 1 in 138,500; late-onset: 1 in 60,000)

Pompe disease is a rare inherited lysosomal storage disorder caused by deficiency of the enzyme acid alpha-glucosidase, ...

Key Symptoms

Progressive muscle weaknessHeart enlargement (cardiomegaly)Breathing difficulties, especially
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Tay-Sachs Disease

1 in 30,000 births; 1 in 3,500 in Ashkenazi Jewish population

Tay-Sachs disease is a rare autosomal recessive lysosomal storage disorder caused by deficiency of the enzyme hexosamini...

Key Symptoms

Progressive developmental regressionLoss of purposefulCherry-red spot on
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Wilson Disease

1 in 30,000 people worldwide

Wilson disease is a rare inherited disorder where the body accumulates toxic levels of copper, primarily in the liver, b...

Key Symptoms

Kayser-Fleischer rings (greenishProgressive liver damageTremor, rigidity, and
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Multi-System

5

Neurological & Neuromuscular

11

Amyotrophic Lateral Sclerosis

About 5,000 new cases per year in the U.S.; approximately 16,000 Americans living with ALS at any given time

Amyotrophic lateral sclerosis is a progressive neurodegenerative disease destroying motor neurons in the brain and spina...

Key Symptoms

Muscle weakness inMuscle twitching (fasciculations)Progressive loss of
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Batten Disease

1 in 12,500 births (varies by type; rare overall)

Batten disease is a rare inherited neurological disorder caused by mutations in genes affecting lysosomal function, lead...

Key Symptoms

Progressive vision lossBlindness usually bySeizures, often progressive
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Charcot-Marie-Tooth Disease

1 in 2,500 people

Charcot-Marie-Tooth disease is one of the most common inherited neurological disorders, affecting peripheral nerves that...

Key Symptoms

Foot weakness causingDistal leg muscleDifficulty walking or
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Duchenne Muscular Dystrophy

1 in 3,500 to 5,000 male births

Duchenne muscular dystrophy is an X-linked genetic disorder causing progressive muscle weakness and degeneration, beginn...

Key Symptoms

Delayed motor milestonesProgressive weakness inDifficulty running, jumping,
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Friedreich Ataxia

1 in 50,000 people

Friedreich ataxia is an autosomal recessive neurodegenerative disease causing progressive damage to the nervous system, ...

Key Symptoms

Progressive loss ofWeakness and spasticitySpeech difficulties and
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Huntington Disease

5-10 per 100,000 people of European descent; lower in other populations

Huntington disease is an autosomal dominant neurodegenerative disorder caused by an expanded CAG trinucleotide repeat in...

Key Symptoms

Involuntary movements (chorea),Slow, jerky movementsRigidity and muscle
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Multiple System Atrophy

2-5 per 100,000 people

Multiple system atrophy is a rare, progressive neurodegenerative disorder characterized by dysfunction of the autonomic ...

Key Symptoms

Orthostatic hypotension (dizzinessParkinsonism or cerebellarVocal tremor and
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Myasthenia Gravis

1 in 5,000 people

Myasthenia gravis is a chronic autoimmune neuromuscular disorder causing muscle weakness and rapid fatigue. Antibodies a...

Key Symptoms

Drooping eyelids (ptosis)Blurred or doubleWeakness in facial
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Rett Syndrome

1 in 9,000 to 15,000 girls

Rett syndrome is a rare genetic neurological disorder affecting brain development, almost exclusively in girls. After no...

Key Symptoms

Developmental regression aroundLoss of purposefulLoss of language
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Spinal Muscular Atrophy

1 in 10,000 to 14,000 births; 1 in 25 people are carriers

Spinal muscular atrophy is an autosomal recessive genetic disorder affecting motor neurons in the spinal cord, causing p...

Key Symptoms

Progressive muscle weaknessDifficulty with motorHypotonia and loss
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Spinocerebellar Ataxia

Collectively about 1-5 per 100,000 people; SCA3 (Machado-Joseph disease) is the most common subtype worldwide

Spinocerebellar ataxias are a group of inherited neurodegenerative disorders caused by mutations in various genes, leadi...

Key Symptoms

Progressive difficulty withSlurred or scanningDifficulty with fine
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Pulmonary & Respiratory

4

Rare Cancers

6

Adrenocortical Carcinoma

About 1-2 per million people per year; approximately 600 new cases per year in the U.S.

Adrenocortical carcinoma is a rare, aggressive cancer of the adrenal cortex, the outer layer of the adrenal glands that ...

Key Symptoms

Rapid, unexplained weightExcess hair growthHigh blood pressure
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Cholangiocarcinoma

About 8,000 new cases per year in the U.S.; rising incidence worldwide

Cholangiocarcinoma is a rare and aggressive cancer that forms in the bile ducts, the thin tubes that carry digestive flu...

Key Symptoms

Jaundice (yellowing ofIntense itching (pruritus)Light-colored or clay-colored
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Gastrointestinal Stromal Tumor

About 4,000-6,000 new cases per year in the U.S.; true incidence may be higher as small GISTs are often incidentally discovered

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, arising fr...

Key Symptoms

Abdominal pain orA feeling ofNausea and vomiting
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Merkel Cell Carcinoma

About 3,000 new cases per year in the U.S.; incidence has tripled over the past 2 decades

Merkel cell carcinoma is a rare, aggressive skin cancer that arises from Merkel cells, specialized touch receptors in th...

Key Symptoms

A firm, painless,Rapidly growing skinUsually appears on
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Mesothelioma

About 3,000 new cases per year in the U.S.

Mesothelioma is a rare, aggressive cancer that develops in the mesothelium, the thin layer of tissue covering most inter...

Key Symptoms

Shortness of breathAbdominal swelling andUnexplained weight loss
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NTRK Fusion Cancer

NTRK fusions occur in less than 1% of all common cancers, but in up to 90% of certain rare tumor types like infantile fibrosarcoma and secretory breast carcinoma

NTRK fusion cancers are a group of rare tumors driven by gene fusions involving 1 of 3 NTRK genes (NTRK1, NTRK2, or NTRK...

Key Symptoms

Symptoms vary widelyA growing lumpFatigue and unexplained
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