Bobble-head doll syndrome (BHDS) is an exceptionally rare pediatric movement disorder in which a child’s head bobs rhythmically 2–3 times per second, usually ...

Bing–Neel syndrome is an exceptionally rare complication of Waldenström macro­globulinemia (WM) in which the same lymphoplasmacytic lymphoma (LPL) cells that ...

Bhaskar–Jagannathan Syndrome (BJS) is an extremely rare, presumably inherited neuro-ocular-skeletal disorder first described in 1974 by the Indian neurologists ...

Benign fasciculation syndrome is a neurological condition in which healthy people experience frequent, spontaneous twitches (“fasciculations”) of the small ...

Benedikt syndrome—also called paramedian midbrain syndrome or red-nucleus syndrome—is a rare stroke-like disorder that happens when a very small area in the ...

Behr syndrome is a rare, inherited neuro-ophthalmological disorder first described in 1909 by Carl Behr. Children typically present before school-age with ...

Beck–Fahrner syndrome is an extremely rare genetic condition caused by pathogenic variants in the TET3 gene on chromosome 2p13.1. The gene encodes ...

Bardet–Biedl syndrome is a ciliopathy—a disorder caused by tiny hair-like “antennae” called primary cilia that stick out from almost every cell in the body. ...

Bannayan–Riley–Ruvalcaba syndrome (BRRS) is a rare, inherited over-growth condition that sits within the wider “PTEN hamartoma tumour syndrome (PHTS)” family. ...

Bálint’s syndrome is an uncommon but striking disorder of higher-order vision and spatial awareness that appears when both parietal-occipital lobes of the ...

Babinski–Nageotte syndrome (BNS) is an alternating medullary brain-stem syndrome that appears when a stroke, tumor, inflammation, or other lesion damages the ...

Athabaskan brainstem dysgenesis syndrome (ABDS) – also called HOXA1-related brain-stem dysgenesis or an HOXA1 syndrome – is an extremely rare genetic condition ...

Ataxia–telangiectasia (A-T) is a rare, inherited, multi-system disorder in which a single gene glitch sabotages the body’s master DNA-repair switch, gradually ...

Arts syndrome is an ultra-rare, X-linked, inherited neurological disorder caused by “loss-of-function” mutations in the PRPS1 gene, which encodes the enzyme ...

Arakawa’s syndrome II (also called methionine-synthase deficiency, tetrahydrofolate-methyl-transferase deficiency, or N5-methyl-homocysteine-transferase ...

Anton syndrome—also called Anton-Babinski syndrome or visual anosognosia—is a rare neurological condition in which a person is cortically blind yet firmly (and ...

Antiphospholipid syndrome is an autoimmune clotting disorder in which “mis-programmed” antibodies (antiphospholipid antibodies, or aPL) stick to phospholipids ...

Anterior spinal artery syndrome—sometimes called anterior cord syndrome or, more colloquially, a “spinal stroke”—happens when blood flow through the anterior ...

Anterior cerebral artery (ACA) syndrome is the cluster of neurological deficits that appears when blood flow through one or both anterior cerebral arteries is ...

Angelman syndrome (AS) is a lifelong genetic condition that affects the way the brain develops. Most cases happen because a piece of DNA on chromosome 15 that ...