A
Aarskog syndrome: A rare genetic disorder causing facial dysmorphia, developmental delays, and other symptoms.
Achondroplasia: A genetic disorder resulting in dwarfism and bone deformities.
Acromegaly: A rare condition where the pituitary gland produces too much growth hormone, causing excessive bone growth and other changes.
Alkaptonuria: A rare metabolic disorder in which an enzyme deficiency causes an accumulation of homogentisic acid, discoloring the connective tissue.
Alport syndrome: A genetic disorder that can cause kidney disease, hearing loss, and eye problems.
Alström syndrome: A rare and complex genetic disorder resulting in a variety of symptoms and medical issues.
Amyotrophic lateral sclerosis (also Lou Gehrig’s disease or motor neuron disease): A progressive neurodegenerative disease that affects the nerve cells responsible for voluntary muscle control.
Amyloidosis: A group of diseases in which abnormal proteins, called amyloid deposits, affect various organs.
Amelogenesis imperfecta: A rare genetic disorder causing insufficient development of tooth enamel.
Angelman syndrome: A neurodevelopmental disorder that causes developmental delay, intellectual disability, and distinctive behavior.
Angioedema: A rare skin condition causing swelling of the skin or mucous membranes.
Apert syndrome: A rare genetic disorder resulting in abnormal growth of the skull, hands, and feet.
Aplastic anemia: A rare form of anemia where the bone marrow does not produce enough blood cells.
Arnold-Chiari malformation: A rare congenital brain anomaly in which part of the brain protrudes through the opening at the base of the skull.
Autoimmune hepatitis: A rare condition where the immune system attacks the liver cells causing inflammation.
B
Bardet-Biedl syndrome: A rare genetic disorder affecting various organ systems and may cause obesity, retinal degeneration, and hearing loss.
Bartter syndrome: A rare genetic disease leading to electrolyte and kidney dysfunction.
Basan syndrome: A rare genetic disorder causing deafness and skin pigment changes.
Berdon syndrome: A rare congenital disorder affecting the urinary system and digestive tract.
Bisphosphoglycerate mutase deficiency: A rare metabolic disorder that causes a unique form of hemolytic anemia.
Bloom syndrome: A rare genetic disorder causing short stature, photosensitivity, and increased cancer risk.
Bloom-Torre-Machacek syndrome: A rare genetic disorder marked by growth abnormalities, intellectual disability, and other anomalies.
Blue rubber bleb nevus syndrome: A rare vascular disorder resulting in multiple abnormal blood vessels (venous malformations).
Brachmann-de Lange syndrome: A rare genetic condition marked by growth delays, intellectual disability, and unique facial features.
Brugada syndrome: A rare heart rhythm disorder that can lead to life-threatening arrhythmias.
C
CADASIL (Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy): A rare genetic disease causing strokes and dementia.
Chediak-Higashi syndrome: A rare genetic disorder impairing lysosomal function, resulting in immune deficiency and albinism.
Chondrodysplasia punctata: A rare genetic disorder causing skeletal abnormalities and intellectual disability.
Chronic inflammatory demyelinating polyneuropathy (CIDP): A rare autoimmune disorder affecting peripheral nerves and causing weakness and sensory loss.
Choroideremia: A rare genetic condition affecting the retina and optic nerve, potentially leading to vision loss.
Cockayne syndrome: A rare, inherited disorder causing premature aging and various physical and intellectual disabilities.
Cowden syndrome: A rare genetic disorder characterized by the growth of benign tumors in various tissues.
CREST syndrome: A rare form of systemic sclerosis leading to changes in skin, blood vessels, digestive organs, and more.
Crouzon syndrome: A rare genetic disorder affecting skull development and resulting in unique facial features.
Cushing’s syndrome: A rare disorder caused by excessive cortisol production leading to various symptoms.
Cystic fibrosis (CF): A rare, inherited metabolic disorder affecting the lungs and digestive system.
D
Dandy-Walker malformation: A rare congenital brain malformation where parts of the cerebellum are missing or underdeveloped.
Déjerine-Sottas syndrome: A rare genetic neuropathy causing progressive weakness and loss of sensation.
Dermatomyositis: A rare inflammatory disease affecting the skin and muscles.
Desmoid tumor: A rare type of tumor arising from connective tissue and can appear in multiple body regions.
Dextrocardia heart defect: A rare congenital heart condition where the heart is located on the right side of the chest.
Diamond-Blackfan anemia: A rare genetic form of aplastic anemia affecting red blood cell production.
Dravet syndrome: A rare genetic epilepsy beginning in childhood and causing severe seizures.
Dubowitz syndrome: A rare genetic disorder characterized by growth delays, intellectual disability, and unique facial features.
Dunbar syndrome: A rare chronic circulatory disorder in the intestine causing nausea, vomiting, cramps, and upper abdominal pain due to compression of the celiac artery (truncus coeliacus).
Dyskeratosis congenita: A rare genetic disorder leading to premature skin aging, bone marrow failure, and increased cancer risk.
Familial dysautonomia: A rare genetic disorder affecting the autonomic nervous system and leading to symptoms such as fainting and cardiac arrhythmia.
E
Ehlers-Danlos syndrome (EDS): A group of rare genetic connective tissue disorders causing hyperflexible joints, fragile skin, and other symptoms.
Ehlers-Danlos syndrome, classic type: A rare EDS form marked by overstretchable skin, joint hyperlaxity, and fragile blood vessels.
Ellis-van Creveld syndrome: A rare genetic disease causing short limbs, heart defects, and other anomalies.
Encephalopathy with status epilepticus during sleep (ESES): A rare epilepsy type with repeated nighttime seizures that may impair cognitive development.
Eosinophilic fasciitis: A rare inflammatory disease affecting the skin and underlying tissue.
Epidermodysplasia verruciformis: A rare genetic disorder causing abnormal skin lesion growth and increased skin cancer risk.
Epidermolysis bullosa (EB): A rare genetic skin disorder that makes skin extremely sensitive and causes blisters and abrasions.
Erdheim-Chester disease: A rare non-Langerhans cell histiocytosis where particular cells infiltrate organs and cause inflammatory changes.
F
Fahr’s syndrome: A rare neurodegenerative disease causing progressive movement disorders, dementia, and brain calcifications.
Familial hypercholesterolemia: A rare inherited disorder causing high cholesterol levels and increased heart disease risk.
Fanconi anemia: A rare genetic disorder causing bone marrow failure and heightened cancer risk.
Farber disease: A rare inherited metabolic disease leading to the buildup of fatty substances (sphingolipids) in organs.
Fechtner syndrome: A rare inherited disorder with blood clots in the kidneys, thrombocytopenia, and sensorineural hearing loss.
Fibrodysplasia ossificans progressiva (FOP): A rare genetic disease where muscles and soft tissues turn into bone, leading to progressive ossification.
Fibromuscular dysplasia (FMD): A rare vascular disease causing abnormal connective tissue growth in artery walls.
Fragile X syndrome: A rare genetic disorder leading to intellectual disabilities and behavioral problems.
Freeman-Sheldon syndrome: A rare genetic disorder causing joint contractures, muscle weakness, and distinctive facial features.
Friedreich’s ataxia: A rare neurodegenerative disease impairing the nervous system and causing movement and coordination issues.
G
Gastrointestinal stromal tumors (GIST): Rare tumors that develop in the stomach or intestines, usually benign but can also be malignant.
Gaucher disease: A rare inherited metabolic disorder where fat lipids (glucocerebrosides) accumulate in cells, causing organ and tissue damage.
Gitelman syndrome: A rare inherited kidney disorder causing electrolyte imbalances and low blood pressure.
Gerstmann-Sträussler-Scheinker syndrome: A rare neurodegenerative disease with nervous system abnormalities and progressive cognitive impairment.
Glanzmann thrombasthenia: A rare inherited bleeding disorder in which platelets do not function properly.
Glutaric aciduria type 1: A rare congenital metabolic disorder where the body cannot break down glutaric acid properly.
Goldenhar syndrome: A rare congenital disorder with features such as an enlarged, recessed or missing eye, ear malformations with absent ear canal, facial asymmetry, chin displacement to the affected side, and vertebral anomalies.
Gorham-Stout syndrome (Gorham’s disease): A rare disorder where abnormal growth replaces bone, causing bone loss and deformity.
Gorlin-Goltz syndrome (nevoid basal cell carcinoma syndrome): A rare genetic disorder causing susceptibility to skin cancer and various anomalies.
Griscelli syndrome: A rare genetic disorder causing silvery hair and immune dysfunction.
Guillain-Barré syndrome (GBS): A rare autoimmune disease causing peripheral nerve inflammation and possible paralysis.
H
Hemochromatosis: A rare genetic disorder where the body absorbs too much iron, leading to iron deposits in organs and tissues.
Hemophagocytic lymphohistiocytosis (HLH): A rare, potentially life-threatening immune disease where certain immune cells attack tissues.
Hereditary angioedema (HAE): Rare genetic conditions causing episodic swellings of the skin or mucous membranes.
Hermansky-Pudlak syndrome (HPS): A rare genetic disorder causing albinism, bleeding tendency, and other issues.
Hurler syndrome (mucopolysaccharidosis type I): A rare inherited metabolic disorder affecting cell recycling and leading to progressive organ damage.
Hutchinson-Gilford progeria syndrome (HGPS): A rare genetic disorder causing rapid aging in children.
Hydatid cyst: A rare parasitic infection caused by Echinococcus larvae forming cysts in organs such as the liver and lungs.
Hypereosinophilic syndrome (HES): A rare disorder with too many eosinophilic granulocytes in the blood, potentially damaging organs.
Hypokalemic periodic paralysis (HOKPP): A rare inherited condition causing episodes of muscle paralysis.
Hypophosphatasia: A rare genetic metabolic disorder with low alkaline phosphatase, leading to weak bones and other issues.
I
Idiopathic pulmonary fibrosis (IPF): A rare lung disease where lung tissue gradually scars, making breathing difficult.
Ichthyosis: A group of rare genetic skin disorders leading to dry, scaly skin.
Immunodeficiencies: A group of rare immune system disorders that can lead to frequent and severe infections.
Incontinentia pigmenti: A rare genetic disease causing skin changes and other symptoms.
Infantile myofibrillar myopathy (MFM): A rare muscle disorder affecting muscle function.
Infantile neuroaxonal dystrophy (INAD): A rare neurodegenerative disease impacting the nervous system, causing developmental delays and movement disorders.
Intracranial hypertension (idiopathic intracranial hypertension): A rare disorder causing increased pressure in the brain, resulting in headaches and vision issues.
Iridogoniodysgenesis (IGD): A rare eye disease impairing iris and angle development.
Isolated aniridia: A rare eye disorder where the iris is completely or partially missing.
Isolated cortical dysplasia: A rare developmental brain disorder where the cerebral cortex is malformed.
J
Jacobsen syndrome: A rare genetic disorder caused by a partial deletion of the long arm of chromosome 11, leading to developmental delay and unique facial features.
Jansen metaphyseal chondrodysplasia: A rare genetic skeletal disorder resulting in bone growth abnormalities.
Jeune syndrome (asphyxiating thoracic dystrophy): A rare genetic disorder causing a narrowed chest and breathing difficulties.
Jervell and Lange-Nielsen syndrome: A rare congenital cardiovascular disorder marked by prolonged QT intervals on ECG and a high risk of life-threatening arrhythmias.
Joubert syndrome: A rare genetic disorder caused by brain anomalies, leading to coordination issues, intellectual disability, and unique facial features.
Juvenile dermatomyositis: A rare inflammatory disease mainly affecting children and youth, causing muscle weakness and skin rashes.
Juvenile myoclonic epilepsy (JME): A rare epilepsy type usually starting in adolescence with myoclonic (involuntary) muscle jerks.
K
Cri-du-chat syndrome (cat cry syndrome): A rare genetic disorder caused by deletion on the short arm of chromosome 5, resulting in unique facial features and intellectual disability.
Kallmann syndrome: A rare genetic disorder affecting the sense of smell and reproductive function.
Kaposi sarcoma: A rare cancer developing in blood vessels or lymphatic vessels, causing skin changes and tumors.
Kartagener syndrome (primary ciliary dyskinesia): A rare genetic disorder involving cilia malfunction, leading to chronic respiratory infections and organ movement issues.
Kawasaki disease: A rare inflammatory disease mainly in children, affecting blood vessels.
Kearns-Sayre syndrome: A rare mitochondrial disorder affecting eyes, heart, and nervous system, causing muscle weakness and vision problems.
Klinefelter syndrome: A rare genetic disorder in which boys have an extra X chromosome (XYY or XXY), leading to developmental delays and hormonal changes.
Kniest dysplasia: A rare genetic skeletal disease causing bone growth anomalies and unique facial features.
Korsakoff syndrome: A rare neurologic disorder causing memory loss, disorientation, and cognitive decline, often due to chronic alcohol misuse.
L
Lafora disease: A rare progressive neurodegenerative condition classified among the “epilepsies with myoclonic seizures”.
Lambert-Eaton myasthenic syndrome (LEMS): A rare autoimmune condition impairing nerve-muscle communication, leading to muscle weakness.
Langerhans cell histiocytosis (LCH): A rare disorder where Langerhans cells accumulate in the body and cause tissue damage.
Laurence-Moon-Biedl-Bardet syndrome: A rare genetic disorder affecting the eyes, brain, and other organs, leading to intellectual disability and obesity.
Leber hereditary optic neuropathy (LHON): A rare mitochondrial disorder causing sudden vision loss.
Leiomyosarcoma: A rare soft tissue cancer arising from smooth muscle cells.
Lentigo maligna melanoma: A rare type of skin cancer developing from lentigo maligna lesions.
Lipoedema: A rare fat tissue disorder where fat accumulates disproportionately and painfully in the limbs.
Lipodystrophy: A rare genetic disease where fat tissue is abnormally distributed, causing insulin resistance and metabolic problems.
Lissencephaly: A rare genetic brain condition where the brain is smooth (lacking the normal folds/grooves), leading to developmental delay.
Lowe syndrome (oculocerebrorenal syndrome): A rare genetic disease affecting the eyes, brain, and kidneys and leading to developmental delay.
Lysosomal storage diseases (LSD): A group of rare genetic disorders caused by buildup of unprocessed substances in lysosomes.
M
Marfan syndrome: A rare genetic disease affecting connective tissue, resulting in long bones, joint problems, and heart complications.
Mastocytosis: A rare disorder where mast cells accumulate abnormally, causing skin changes, digestive problems, and other symptoms.
Metachromatic leukodystrophy: A rare progressive inherited nervous system disease among leukodystrophies.
Microcephalic primordial dwarfism syndrome (MOPD): A rare genetic disorder with a very small head circumference and growth impairment.
Wilson’s disease: A rare genetic disorder in which the body cannot metabolize copper properly, leading to a buildup in the liver, brain, and other organs.
Moyamoya disease: A rare vascular disorder narrowing brain blood vessels and increasing stroke risk.
Mucinosis: A rare group of disorders with accumulation of mucin in the connective tissue.
Mucolipidosis: An autosomal recessive genetic defect, even rarer than mucopolysaccharidosis.
Mucopolysaccharidosis (MPS): A group of rare inherited metabolic diseases with enzyme deficiencies for breaking down mucopolysaccharides (glycosaminoglycans).
Multiple sclerosis (MS): A rare autoimmune disorder where the immune system attacks the myelin sheath of nerves in the central nervous system.
Myasthenia gravis: A rare autoimmune disease impairing nerve–muscle signal transmission, causing weakness.
Myelodysplastic syndrome (MDS): A rare group of bone marrow diseases where too few healthy blood cells are produced.
N
Narcolepsy: A rare neurological sleep disorder causing excessive daytime sleepiness, sudden sleep episodes, and cataplexy (muscle control loss).
NEDAMSS: A rare disease caused by IRF2BPL gene mutation resulting in developmental disorders.
Nephronophthisis: A rare inherited kidney disease leading to kidney failure.
Netherton syndrome: A rare genetic skin disease increasing infection and allergy risk.
Neuroblastoma: A rare cancer that develops in immature nerve cells, mainly in children.
Neurofibromatosis: A rare genetic disorder affecting the nervous system with tumor growth on nerves.
Neuromyelitis optica (NMO): A rare autoimmune disorder affecting the central nervous system, causing inflammation of the optic nerve and spinal cord.
Neuronal ceroid lipofuscinosis (NCL): A rare inherited disorder causing lipid buildup in cells and progressive neurological impairment.
Neutropenia: A rare blood disorder with low numbers of neutrophils (a type of white blood cell), increasing infection risk.
Niemann-Pick disease: A rare genetic metabolic disorder causing fat buildup in cells, impacting multiple organs.
Noonan syndrome: A rare genetic disorder leading to distinctive features and developmental delays.
O
Ohtahara syndrome: A rare severe epilepsy in infants leading to seizures and developmental delay.
Oculocutaneous albinism: A rare genetic disorder causing skin and hair albinism as well as vision problems.
Ondine syndrome (congenital central hypoventilation syndrome): A rare genetic disorder where the autonomic nervous system fails to control breathing properly.
Opsoclonus-myoclonus syndrome (OMS): A rare neurological disease causing uncoordinated eye movements (opsoclonus) and muscle jerks (myoclonus).
Orofaciodigital syndrome (OFD): A rare genetic disorder affecting the face, mouth, and fingers, resulting in characteristic features.
Osteogenesis imperfecta (brittle bone disease): A rare genetic bone disorder where bones are fragile and prone to fracture.
P
Pallister-Killian syndrome: A rare genetic disorder causing physical and intellectual disabilities, unique facial features, and other abnormalities.
Pantothenate kinase-associated neurodegeneration (PKAN): A rare neurodegenerative disease causing movement disorders, dementia, and other neurological problems.
Paraneoplastic pemphigus: A rare autoimmune disorder affecting the skin and mucous membranes associated with specific cancers.
Phelan-McDermid syndrome (PMS): A rare genetic disorder caused by a deletion on the long arm of chromosome 22.
Phenylketonuria (PKU): A rare inherited metabolic disorder where the body can’t break down phenylalanine, resulting in its accumulation in the blood. Untreated, it can cause intellectual disability and other problems.
POEMS syndrome: A rare paraneoplastic disorder characterized by symptoms such as polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes.
Polyarteritis nodosa: A rare inflammatory vascular disease causing tissue damage and possibly affecting multiple organs.
Polymyositis: A rare inflammatory muscle disease causing weakness and muscle inflammation.
Pontocerebellar hypoplasia (PCH): A rare neurological disorder causing underdevelopment of certain brain regions.
Porphyria: A group of rare inherited metabolic diseases involving an enzyme deficiency in making heme, part of red blood pigment.
Postural tachycardia syndrome (POTS): A rare autonomic dysfunction where heart rate rises abnormally with body position changes.
Prader-Willi syndrome: A rare genetic disorder causing developmental delays, obesity, and behavioral problems.
Pulmonary alveolar proteinosis (PAP): A rare lung disease causing accumulation of protein-rich fluid in the alveoli.
Pulmonary hypertension: A rare disorder with high blood pressure in the lung arteries, leading to breathing difficulties and heart issues.
PURA syndrome: A rare, genetic neurodevelopmental disorder causing intellectual disability and muscle weakness, among other issues.
Q
Q fever (query fever): A rare bacterial infection caused by Coxiella burnetii, causing flu-like symptoms.
Quadratus lumborum syndrome: A rare muscular disorder causing lower back pain and tension.
Quincke’s edema: A rare swelling reaction of the skin and mucous membranes caused by sudden release of histamine and other mediators.
Querulant paranoia: A rare psychiatric disorder where sufferers are convinced they are victims of a conspiracy or injustice.
Quick syndrome (acalculous periarthritis): A rare disease of painful inflammation of tendon and bursa in the shoulder.
Quincke syndrome (hereditary angioedema): A rare genetic disorder causing episodic skin and mucous membrane swelling.
Quintero stages I-IV: A rare classification of fetal anomalies with polyhydramnios and growth impairment, leading to reduced fetal viability.
R
Ramsay Hunt syndrome: A rare form of shingles affecting the facial nerves, causing facial paralysis and ear pain.
Renal osteodystrophy syndrome: A rare genetic disorder causing bone and kidney problems.
Retinoblastoma: A rare eye cancer mostly in children, arising from retinal cells.
Rett syndrome: A rare genetic disorder affecting mostly girls, causing developmental delay, loss of skills, and intellectual disability.
Reye syndrome: A rare, severe disorder mainly in children, impacting the brain and liver—often linked to prior viral infection.
Riley-Day syndrome (familial dysautonomia): A rare inherited disorder of the autonomic nervous system, affecting pain perception, temperature regulation, and more.
Ring chromosome syndrome: A rare genetic disorder where all or part of a chromosome forms a ring, causing various symptoms.
Romano-Ward syndrome: A rare form of congenital long-QT syndrome causing life-threatening heart arrhythmias.
Russell-Silver syndrome: A rare growth disorder causing short stature, developmental delay, and unique facial features.
S
Sarcoidosis: A rare inflammatory disease causing granulomas in various organs, especially lungs and lymph nodes.
Schwartz-Jampel syndrome: A rare genetic disorder causing muscle stiffness, bone deformities, and distinctive facial features.
Sickle cell anemia: A rare inherited blood disease with abnormally shaped red blood cells, leading to anemia and complications.
Shwachman-Diamond syndrome: A rare genetic disease causing bone marrow failure, digestive issues, and more.
Simpson-Golabi-Behmel syndrome: A rare genetic disease mainly affecting boys with multiple physical features and development issues.
Sjögren syndrome: A rare autoimmune disorder primarily affecting salivary and tear glands, causing dry eyes and mouth.
Smith-Magenis syndrome: A rare genetic disorder with developmental delays, behavioral issues, and unique facial features.
Spinal muscular atrophy (SMA): A rare genetic disorder affecting nerve cells in the spinal cord leading to muscle weakness and atrophy.
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN): Rare, severe skin reactions to medications or infections causing severe blisters and skin detachment.
Stiff-person syndrome: A rare neurological condition causing uncontrolled muscle stiffness and spasms.
Sturge-Weber syndrome: A rare neurological disorder with abnormal blood vessels in the brain and face, causing seizures and neurological issues.
T
Tay-Sachs disease: A rare genetic metabolic disorder where enzyme deficiency leads to accumulation of a substance in nerve cells. This causes progressive neurological impairment and intellectual disability.
Thrombocytopenia-absent radius syndrome: A rare genetic disorder with low blood platelets and arm abnormalities.
Treacher Collins syndrome: A rare genetic disorder affecting the face/skull, leading to features such as abnormal ears and jaw.
Triple X syndrome (XXX syndrome): A rare genetic disorder in women with three X chromosomes causing variable impacts on growth and development.
Trisomy 13 (Patau syndrome): A rare genetic disorder with an extra chromosome 13, causing severe development and organ defects.
Trisomy 18 (Edwards syndrome): A rare genetic disorder in which an extra chromosome 18 results in severe developmental and heart defects.
Trisomy 21 (Down syndrome): A rare genetic disorder with an extra chromosome 21, causing intellectual disability and distinctive features.
Tuberous sclerosis: A rare genetic disorder causing benign tumors in multiple organs and neurological problems.
Turner syndrome: A rare condition only in females, characterized by missing or partially missing X chromosome, leading to growth and ovarian problems.
Tyrosinemia: A rare genetic disorder causing disruption in tyrosine metabolism, leading to liver and kidney problems.
U
Ulnar clinodactyly syndrome: A rare genetic disease causing a lateral curvature of the little finger.
Ullrich congenital muscular dystrophy: A rare form of muscular dystrophy present from birth, leading to muscle weakness, stiff joints.
Ulrich syndrome (Alport syndrome): A rare genetic disease affecting kidneys, hearing, and eyes, causing kidney failure and hearing loss.
Ondine syndrome (congenital central hypoventilation syndrome): A rare genetic disorder where the autonomic nervous system fails to regulate breathing.
Urea cycle disorders: A group of rare inherited disorders causing failure to break down ammonia, leading to toxic accumulation in the blood and can be life-threatening.
Urticarial vasculitis: A rare type of hives (urticaria) affecting blood vessels, causing skin rashes and inflammation.
Usher syndrome: A rare inherited disorder causing deafness or hearing loss combined with progressive retinitis pigmentosa and vision loss.
Uterus didelphys: A rare birth defect where the uterus is divided into two separate halves.
Uveal melanoma: A rare eye cancer arising from pigmented eye cells.
V
Van der Woude syndrome: A rare genetic disorder causing facial malformations such as cleft lip and palate.
Allergic vasculitis: A rare type of vasculitis caused by allergic reaction and leading to skin rashes and inflammation.
Vascular Ehlers-Danlos syndrome (VEDS): A rare genetic disorder of connective tissue causing dangerous vascular ruptures and internal organ tears.
VATER syndrome (VACTERL association): A rare disorder with multiple birth defects including spine, anal, heart, and kidney anomalies.
Velocardiofacial syndrome (VCFS, DiGeorge syndrome): A rare genetic disorder causing heart defects, facial features, and immune dysfunction.
Villous adenomas: Rare polyps found in the colon that increase cancer risk.
Vitamin B12 transport defect: A rare metabolic disorder impairing transport/utilization of vitamin B12.
Vogt-Koyanagi-Harada syndrome: A rare autoimmune disease affecting the eyes, skin, CNS, causing uveitis and vision loss.
Volles-Stand-In syndrome: A rare genetic disorder causing severe intellectual disability, epilepsy, and muscle stiffness.
Von Hippel-Lindau syndrome: A rare genetic disorder leading to tumors and cysts in various organs.
W
Walker-Warburg syndrome: A rare congenital disorder marked by brain malformations, muscle weakness, eye problems, and other features.
WAGR syndrome (Wilms tumor, aniridia, genital anomalies, intellectual disability): A rare genetic disorder with kidney cancer, aniridia, genital anomalies, and intellectual disability.
Weill-Marchesani syndrome: A rare genetic disease causing short stature, cataracts, muscle weakness, and joint stiffness.
Werner syndrome: A rare genetic disease causing rapid aging, premature gray hair, skin changes, cataracts, diabetes, and more.
Wiskott-Aldrich syndrome (WAS): A rare inherited immune disorder mainly affecting boys.
Wolfram syndrome (DIDMOAD syndrome): A rare genetic disorder including diabetes insipidus (DI), diabetes mellitus (type 1), optic atrophy, hearing loss, and motor impairment.
X
Xanthelasma: A rare skin disorder causing yellowish fat deposits under the skin near the eyes.
Xanthinuria: A rare metabolic disorder causing increased excretion of xanthine and hypoxanthine in urine.
Xanthomatosis: A rare metabolic disorder causing fat deposits in skin and tendons.
X-linked adrenoleukodystrophy (ALD): A rare inherited disorder destroying myelin sheaths in brain/nerves, leading to neurological symptoms.
X-linked agammaglobulinemia: A rare genetic disorder with B-lymphocyte deficiency, compromising immunity and causing severe infections.
X-linked hyper IgM syndrome: A rare genetic disorder where the immune system does not produce enough IgM, causing infection susceptibility.
X-linked lymphoproliferative syndrome: A rare genetic disease with excessive immune response to certain viruses, leading to life-threatening complications.
X-linked retinoschisis: A rare genetic disorder affecting the retina and causing vision problems or retinal detachment.
X-linked spastic paraplegia (SPG): A rare genetic disorder causing progressive leg muscle weakness and spasticity.
Xeroderma pigmentosum: A rare genetic disease making skin highly sensitive to UV light, greatly increasing skin cancer risk.
Y
Yaws: A rare bacterial infection caused by Treponema pallidum pertenue, leading to skin lesions and bone changes.
Yellow nail syndrome: A rare disorder where nails become yellowish, the lymphatic system is affected, and lymphedema develops.
Yersinia pestis: A rare but potentially deadly bacterial infection causing severe flu-like symptoms and lymph node swelling.
Y-linked inheritance: A rare inheritance form where a gene on the Y chromosome is passed from father to son only.
Yorifuji-Okuno syndrome: A rare genetic disorder marked by developmental delay, intellectual disability, and distinctive facial features.
Z
Cerebellar ataxia: A group of rare neurological disorders impairing movement coordination, balance, and fine motor skills.
Zimmermann-Laband syndrome: A rare genetic disorder causing growth impairment, intellectual disability, finger/toe changes, and other anomalies.
Cystic fibrosis (mucoviscidosis): A rare but serious inherited metabolic disorder affecting the lungs, pancreas, and other organs, leading to chronic breathing issues and digestive problems.