1,527 articles
Best vitelliform macular dystrophy
Best vitelliform macular dystrophy (BVMD, Best disease, VMD2) is an autosomal dominant childhood-onset macular dystrophy caused by BEST1 chloride-channel mutations, with egg-yolk macular lesions, low EOG Arden ratio, good prognosis, and an OPGx-BEST1 gene therapy trial recruiting.
Beta-propeller protein-associated neurodegeneration
BPAN (SENDA, NBIA5) is a rare X-linked dominant NBIA disorder caused by WDR45 variants, causing childhood seizures and developmental delay, then parkinsonism, dystonia, and dementia in early adulthood.
Bickerstaff brainstem encephalitis
Bickerstaff brainstem encephalitis (BBE), or Bickerstaff encephalitis, is a rare post-infectious autoimmune brainstem disorder with ophthalmoplegia, ataxia, and impaired consciousness, part of the anti-GQ1b antibody syndrome with Miller Fisher syndrome and Guillain-Barré syndrome.
Bilateral acute depigmentation of the iris
Bilateral acute depigmentation of the iris (BADI) is a rare eye disorder causing sudden pigment loss in both irises, with photophobia and red eye that usually resolves on its own.
Bilateral diffuse uveal melanocytic proliferation disease
BDUMP (bilateral diffuse uveal melanocytic proliferation, paraneoplastic uveal melanocytic hyperplasia) is a rare paraneoplastic syndrome of benign uveal melanocyte proliferation from occult cancer, causing bilateral vision loss, cataracts, and retinal detachment.
Bilateral striopallidodentate calcinosis
Bilateral striopallidodentate calcinosis, also known as primary familial brain calcification or Fahr's disease, is a rare inherited disorder marked by calcium deposits in the basal ganglia.
Biotin-thiamine-responsive basal ganglia disease
Biotin-thiamine-responsive basal ganglia disease (BTBGD), also called thiamine transporter-2 deficiency, is a rare autosomal recessive disorder from SLC19A3 mutations, causing episodic encephalopathy and movement problems in childhood, reversible with high-dose biotin and thiamine.
Birdshot chorioretinopathy
Birdshot chorioretinopathy (birdshot retinochoroidopathy, HLA-A29 uveitis) is a rare chronic bilateral posterior uveitis of middle-aged Europeans, strongly linked to HLA-A29, causing cream-colored choroidal spots and progressive vision loss.
Birth depression
Birth depression (ICD-11 KD30) is cardiorespiratory and neurological depression in a newborn, graded by 5-minute Apgar score (0-3, 4-6) or cord-blood metabolic acidaemia; distinct from maternal perinatal depression.
Björnstad syndrome
Björnstad syndrome (OMIM 262000, Crandall syndrome) is a rare autosomal recessive BCS1L mitochondrial disorder causing congenital sensorineural hearing loss and pili torti, with fewer than fifty reported cases.
Blake pouch cyst
Blake pouch cyst (Blake's pouch cyst, BPC), a usually benign posterior fossa cystic malformation from failure of the fourth ventricular tela choroidea to regress; intact rotated vermis, favorable outcome, part of the Dandy–Walker spectrum.
Blepharitis
Blepharitis, inflammation of the eyelid margins, is a common chronic eye condition. Types include anterior (staphylococcal, seborrheic), posterior (meibomian gland dysfunction), and Demodex blepharitis; treatment centers on lid hygiene.
Blepharophimosis-intellectual disability syndrome, MKB type
Blepharophimosis-intellectual disability syndrome, MKB type (X-linked Ohdo syndrome, BMRS Maat-Kievit-Brunner type) is a rare X-linked recessive MED12 disorder in males with intellectual disability, blepharophimosis, ptosis, and coarsening triangular facies.
Blepharophimosis-ptosis-epicanthus inversus syndrome
BPES (blepharophimosis-ptosis-epicanthus inversus syndrome), also called blepharophimosis syndrome, is a rare autosomal dominant FOXL2-related eyelid malformation with ptosis, telecanthus, and sometimes primary ovarian insufficiency.
Blue cone monochromatism
Blue cone monochromatism (blue cone monochromacy, S-cone monochromatism) is a rare X-linked recessive retinal disorder caused by OPN1LW/OPN1MW mutations at Xq28 that inactivate red and green cones, leaving rods and blue cones, with nystagmus, photophobia, myopia, and acuity about 6/24 to 6/60.
Blue sclera
Blue sclera (blue sclerae), ICD-11 LA11.0: a blue, gray, or purplish tint of the eye's white sclera from translucency letting the uvea show through. Causes include osteogenesis imperfecta, Marfan and Ehlers-Danlos syndromes, iron deficiency, and drugs such as minocycline.
BOR syndrome
BOR syndrome (branchiootorenal, Melnick-Fraser syndrome) is a rare autosomal dominant disorder of branchial arches, ears, and kidneys, mainly caused by EYA1 or SIX1 variants, with hearing loss in over 90% and CAKUT in 67%.
Borjeson-Forssman-Lehmann syndrome
Borjeson-Forssman-Lehmann syndrome (BFLS, Börjeson syndrome) is a rare X-linked recessive neurodevelopmental disorder caused by PHF6 variants at Xq26, causing intellectual disability, obesity, hypogonadism, hypotonia, and coarse facies, mainly in males.
Borna virus encephalitis
Borna virus encephalitis, or BoDV-1 encephalitis, is a rare, mostly fatal zoonotic meningoencephalitis of central Europe, spread by the bicolored white-toothed shrew, confirmed in humans in 2018, with about 50 cases and no established therapy.
Bosley-Salih-Alorainy syndrome
Bosley-Salih-Alorainy syndrome (BSAS, OMIM 601536) is a rare autosomal recessive HOXA1-related disorder with bilateral Duane retraction syndrome type 3, deafness, cerebrovascular and cardiac anomalies, and sometimes autism, without central hypoventilation.
Bradyopsia
Bradyopsia (PERRS, prolonged electroretinal response suppression), a rare autosomal recessive retinal disorder from RGS9 or RGS9BP mutations, causing markedly delayed light-dark adaptation, difficulty tracking moving objects, mild photophobia, and reduced acuity with normal color vision.
Brain dopamine-serotonin vesicular transport disease
Brain dopamine-serotonin vesicular transport disease (PKDYS2, brain monoamine vesicular transport disease) is a rare autosomal recessive infantile-onset disorder caused by SLC18A2 mutations impairing VMAT2, causing dystonia, parkinsonism, autonomic dysfunction, and developmental delay; dopamine agonists help while levodopa worsens.
Brain on Fire
Brain on Fire: Susannah Cahalan's 2012 memoir (also a 2016 Netflix film with Chloë Grace Moretz) about her 2009 psychosis and seizures, diagnosed by Dr. Souhel Najjar as anti-NMDA receptor encephalitis, the 217th known case.
Brain tumor
Brain tumor: abnormal cell growth in the brain or CNS; primary tumors (gliomas, meningiomas) versus metastatic tumors, WHO grades I-IV, molecular classification, symptoms, diagnosis, treatment, and survival statistics.
Brain-lung-thyroid syndrome
Brain-lung-thyroid syndrome (BLTS, NKX2-1-related disorder, choreoathetosis-hypothyroidism-neonatal respiratory distress syndrome) is a rare autosomal dominant disorder caused by NKX2-1 (TITF1) mutations at 14q13.3, combining congenital hypothyroidism, infant respiratory distress syndrome, and benign hereditary chorea.
Brainstem haemorrhage
Brainstem haemorrhage (ICD-11 8B00.2) is bleeding in the midbrain, pons, or medulla; primary pontine hemorrhage is the most fatal intracerebral hemorrhage subtype, mainly hypertensive, managed conservatively.
Brainstem lesion
Brainstem lesion: abnormal tissue in the midbrain, pons, or medulla from vascular, neoplastic, inflammatory, infectious, metabolic, or traumatic causes; diagnosed mainly by MRI, classified focal or diffuse, with crossed cranial nerve and body signs.
Brainstem stroke syndrome
Brainstem stroke syndrome is stroke affecting the midbrain, pons, and medulla, accounting for roughly 10% to 15% of strokes; its hallmark is crossed deficits, and severe cases can cause locked-in syndrome.
Branchiootic syndrome
Branchiootic syndrome is a rare autosomal dominant hereditary disorder marked by branchial cysts and fistulae, malformations of the outer, middle, and inner ear, and hearing loss, with normal kidneys.
Brooke Eby
Brooke Eby, ALS advocate and TikTok creator (@LimpBroozkit), diagnosed 2022 at 33, raised over $1 million, founded ALStogether, named ALS Hero 2024, died October 1, 2026 at 37.