All articles starting with S
44,216 articles
Spinocerebellar ataxia type 4
Spinocerebellar ataxia type 4 (SCA4) is a rare autosomal dominant ataxia with sensory neuropathy caused by a GGC repeat expansion in ZFHX3 encoding polyglycine, linked to 16q22.1 in 1996 and solved in 2024 by long-read sequencing.
Spinocerebellar ataxia type 40
Spinocerebellar ataxia type 40 (SCA40, OMIM 616053) is an extremely rare autosomal dominant ataxia caused by CCDC88C missense mutations at 14q32, first reported in 2014, causing adult-onset spastic ataxia with pontocerebellar atrophy via JNK pathway activation.
Spinocerebellar ataxia type 41
Spinocerebellar ataxia type 41 (SCA41, OMIM 616410) is a rare autosomal dominant cerebellar ataxia caused by gain-of-function TRPC3 mutations, first the p.Arg762His variant, causing adult-onset ataxic gait and Purkinje cell degeneration.
Spinocerebellar ataxia type 42
Spinocerebellar ataxia type 42 (SCA42, OMIM 616795) is a rare autosomal dominant cerebellar ataxia caused by CACNA1G (Cav3.1 T-type calcium channel) missense mutations, chiefly p.Arg1715His, causing slowly progressive gait ataxia, dysarthria, and nystagmus.
Spinocerebellar ataxia type 43
Spinocerebellar ataxia type 43 (SCA43, OMIM 617018) is a rare autosomal dominant, adult-onset, slowly progressive cerebellar ataxia with axonal peripheral neuropathy, caused by heterozygous missense mutation in MME (neprilysin) at 3q25.2.
Spinocerebellar ataxia type 45
Spinocerebellar ataxia type 45 (SCA45, OMIM 617769) is a rare autosomal dominant pure cerebellar ataxia caused by missense FAT2 mutations, with late-onset gait ataxia, dysarthria, nystagmus, and cerebellar atrophy.
Spinocerebellar ataxia type 46
Spinocerebellar ataxia type 46 (SCA46, OMIM 617770) is a rare autosomal dominant, adult-onset cerebellar ataxia with sensory axonal neuropathy, linked to a PLD3 p.Leu308Pro mutation reported in a single Dutch family; the gene link is disputed.
Spinocerebellar ataxia type 48
Spinocerebellar ataxia type 48 (SCA48, OMIM 618093) is a rare autosomal dominant ataxia from heterozygous STUB1 mutations at 16p13.3, causing adult-onset gait ataxia, cognitive decline, and movement disorders; biallelic STUB1 variants cause SCAR16.
Spinocerebellar ataxia type 5
Spinocerebellar ataxia type 5 (SCA5), or Lincoln ataxia, a rare autosomal dominant pure cerebellar ataxia caused by SPTBN2 mutations encoding beta-III spectrin; mean onset 33 years, very slow progression, five reported families.
Spinocerebellar ataxia type 6
Spinocerebellar ataxia type 6 (SCA6), an autosomal dominant ataxia from CAG repeat expansion in CACNA1A (Cav2.1 calcium channel), causing late-onset, slowly progressive pure cerebellar ataxia with nystagmus; slowest-progressing common SCA.
Spinocerebellar ataxia type 7
Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant neurodegenerative disease caused by a CAG repeat expansion in the ATXN7 gene, causing progressive ataxia and blindness from cone-rod retinal dystrophy.
Spinocerebellar ataxia type 8
Spinocerebellar ataxia type 8 (SCA8), also called ATXN8OS/ATXN8 CTG expansion ataxia, is a rare autosomal dominant cerebellar ataxia on chromosome 13q21 with reduced penetrance, slow progression, and variable phenotype including tremor and parkinsonism.
Spinocerebellar ataxia with axonal neuropathy type 1
SCAN1 (OMIM 607250) is a rare autosomal recessive ataxia caused by TDP1 p.His493Arg, featuring late-childhood cerebellar ataxia, distal axonal neuropathy, cerebellar atrophy, and hypoalbuminemia, distinct from AOA1 by absent oculomotor apraxia.
Spinocerebellar ataxia with axonal neuropathy type 2
Spinocerebellar ataxia with axonal neuropathy type 2, also called AOA2 or SCAR1, is a rare autosomal recessive cerebellar ataxia caused by biallelic SETX mutations, with onset ages 3-30, sensorimotor neuropathy in 90-100%, oculomotor apraxia in about half, and elevated serum alpha-fetoprotein.
Spinocerebellar ataxia with epilepsy
Spinocerebellar ataxia with epilepsy (SCAE), now classified as myoclonic epilepsy myopathy sensory ataxia (MEMSA), is a rare autosomal recessive disorder caused by POLG mutations, causing ataxia, epilepsy, and cognitive decline.
Spinocyrtia
Spinocyrtia is an extinct spiriferid brachiopod genus (family Spinocyrtiidae) named by Frederiks in 1916, type species Delthyris granulosa Conrad 1839, cosmopolitan in Middle Devonian seas (Eifelian-Givetian, 394.3-378.9 Ma).
Spinodal decomposition
Spinodal decomposition is a mechanism of phase separation where a homogeneous solution spontaneously splits into distinct phases with no nucleation barrier, contrasting with classical nucleation.
Spinon
A spinon is a charge-neutral quasiparticle with spin 1/2 that emerges in quantum magnets whose spins fail to order, notably quantum spin liquids proposed by Philip Anderson in 1973.
Spinor
A spinor is a mathematical object used in quantum physics that changes sign under a full 360-degree rotation, describing spin-1/2 particles like electrons and neutrinos.
Spinor representation
The spinor representation, also called the spin representation, is the simplest faithful linear representation of the spinor group, equivalently of an even Clifford algebra; in even dimension it splits into two half-spinor representations.
Spinosad
Spinosad, a mixture of spinosyns A and D from the actinomycete Saccharopolyspora spinosa, is an IRAC Group 5 insecticide acting on nicotinic acetylcholine receptors, registered since 1997 and used on over 250 crops.
Spinosauridae
Spinosauridae: family of sail-backed, fish-eating theropod dinosaurs with narrow crocodilian snouts, first named via Spinosaurus (Stromer, 1915); semiaquatic wading piscivores of Europe, Africa, South America, and Asia.
Spinosaurus
Spinosaurus (S. aegyptiacus) is a giant sail-backed, fish-eating theropod dinosaur from Late Cretaceous North Africa, named by Stromer in 1915; the longest known carnivorous dinosaur, at the center of a semiaquatic-lifestyle debate.
Spinosaurus mirabilis
Spinosaurus mirabilis, second named Spinosaurus species, described in Science in February 2026 from Niger; scimitar-shaped head crest up to 0.5 m tall, fish-eating, lived about 95 million years ago in inland Saharan rivers.
Spinothalamic tract
The spinothalamic tract, or spinal lemniscus, is a nerve fiber bundle that conveys sensations of pain, temperature, and crude touch from the spinal cord to the thalamus.
Spinous cell
Spinous cells (prickle cells) are keratinocytes of the stratum spinosum, the epidermal layer above the basal layer; named for desmosomal spines, they express K1/K10 and become granular cells.
SpinQ Technology (量旋科技)
SpinQ Technology, also known as 量旋科技, is a Chinese quantum computing company founded in 2018 in Shenzhen, developing superconducting quantum computers and desktop NMR devices.
Spinrilla
Spinrilla was an American mixtape streaming service for hip-hop, launched in 2013 by Jeffery Dylan Copeland and shut down in 2023 after a $50 million judgment.
Spinster
Spinster: originally a 14th-century occupational term for a woman who spins yarn, later the legal title for an unmarried woman in English records until the 20th century, now pejorative but reclaimed by contemporary textile artists.
SPINT1
SPINT1 (serine peptidase inhibitor, Kunitz type 1; HAI-1) is a human chromosome 15 gene encoding a membrane-bound Kunitz-type epithelial protease inhibitor that suppresses matriptase, chaperones its trafficking, and is essential for placental, skin, and intestinal integrity.