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Choreoacanthocytosis
Choreoacanthocytosis (chorea-acanthocytosis, ChAc, VPS13A disease, formerly Levine-Critchley syndrome) is a rare autosomal recessive neurodegenerative disorder caused by VPS13A mutations, with chorea, orofacial dystonia with tongue biting, seizures, acanthocytes, and striatal atrophy.
Chorh-Chuan Tan
Chorh-Chuan Tan is a Singaporean nephrologist who led the 2003 SARS response and served as President of the National University of Singapore from 2008 to 2017.
Chorioallantoic membrane model
The chorioallantoic membrane (CAM) model is an in vivo assay using the chicken embryo's richly vascularized membrane to measure angiogenesis, tumor growth, and drug responses, bridging in vitro experiments and mammalian animal studies.
Choriocarcinoma
Choriocarcinoma is a malignant, fast-growing trophoblastic cancer, usually gestational (after molar or normal pregnancy) and hCG-secreting, spreading via blood to lungs; highly curable with chemotherapy (EMA-CO), overall cure about 94%.
Choriogonadotropin alfa
Choriogonadotropin alfa (Ovidrel, Ovitrelle) is recombinant human chorionic gonadotropin made in CHO cells, approved by FDA in 2000 and EMA in 2001 to trigger ovulation and follicular maturation in fertility treatment.
Chorion
Chorion: the outermost extra-embryonic membrane of amniote embryos. In reptiles and birds it lines the shell for gas exchange; in mammals it develops villi and forms the fetal part of the placenta; also a noncellular fish and insect egg membrane.
Chorion protein
Chorion proteins (chorionin) are insect eggshell structural proteins secreted by follicle cells during choriogenesis; Drosophila has six major cps, silkmoths over 100, hardened by peroxidase tyrosine crosslinks.
Chorionic villus sampling
Chorionic villus sampling (CVS) is a prenatal diagnostic procedure that samples placental tissue under ultrasound guidance, usually at 10 to 13 weeks, to detect chromosomal and genetic abnormalities.
Chorioretinal scars
Chorioretinal scars (ICD-11 9B62, ICD-10 H31.0) are fibrous scars in the choroid and retina from infection such as toxoplasmosis, laser photocoagulation, trauma, or inflammatory disease; vision is affected only when the macula is involved.
Chorismate synthase
Chorismate synthase (EC 4.6.1.4, aroC) is the seventh and final shikimate pathway enzyme, converting EPSP to chorismate via a 1,4-anti-elimination that uniquely requires reduced FMN despite no net redox change; absent from animals, a drug target.
Choristoneura fumiferana
Choristoneura fumiferana, the spruce budworm, is a tortricid moth whose larvae defoliate balsam fir and spruce in North American boreal forests, causing recurring outbreaks at roughly 35-year intervals that can exceed 50 million hectares.
Choristoneura occidentalis
Choristoneura occidentalis (western spruce budworm, formerly C. freemani) is a North American tortricid moth whose larvae defoliate Douglas-fir, firs, larch, and spruce; an EPPO A1 quarantine pest with 30-40 year outbreak cycles.
Choristoneura rosaceana
Choristoneura rosaceana, the obliquebanded leafroller (OBLR), is a North American tortricid moth pest of apple, pear, and other Rosaceae, univoltine or bivoltine by latitude, with documented broad-spectrum insecticide resistance including over 700-fold resistance to indoxacarb.
Choroid
The choroid is the pigmented vascular middle layer of the eye (part of the uvea) supplying the outer retina and RPE, with five layers from Bruch's membrane to the suprachoroid, fed by posterior ciliary arteries and drained by 4-7 vortex veins.
Choroid plexus
Choroid plexus: secretory epithelial tissue in the brain's four ventricles that produces most cerebrospinal fluid, forms the blood-CSF barrier via tight junctions, and aids immune surveillance.
Choroid plexus carcinoma
Choroid plexus carcinoma (CPC), WHO grade 3 malignant choroid plexus tumor, rare aggressive pediatric brain tumor causing hydrocephalus; TP53/Li-Fraumeni linked; treated by resection plus chemotherapy.
Choroid plexus cyst
Choroid plexus cyst (CPC), a fluid-filled cyst in the choroid plexus, found in 0.5–2.5% of second-trimester fetuses; usually resolves by 26–28 weeks; isolated cysts are benign, but CPCs can mark trisomy 18 risk when other findings are present.
Choroidal and ciliary body melanoma
Choroidal and ciliary body melanoma, also called posterior uveal melanoma, is the most common primary intraocular malignancy in adults, arising in the choroid (85–90%) or ciliary body (5–8%), treated mainly by plaque brachytherapy, proton therapy, or enucleation.
Choroidal degeneration
Choroidal degeneration (脈絡膜変性), ICD-11 code 9B60, is progressive atrophy of the choroid, the eye's vascular layer, covering hereditary forms such as choroideremia, gyrate atrophy, and central areolar choroidal dystrophy, plus age-related choroidal atrophy.
Choroidal detachment
Choroidal detachment: fluid or blood accumulating in the suprachoroidal space between choroid and sclera. Serous form follows surgical hypotony, most often after trabeculectomy; hemorrhagic form (suprachoroidal hemorrhage) follows ciliary artery rupture, with guarded vision.
Choroidal dystrophy
Choroidal dystrophy, also called choroidal dystrophies, is an inherited degenerative eye disorder of the choroid, RPE, and photoreceptors, including choroideremia, gyrate atrophy, and central areolar choroidal dystrophy, causing night blindness and peripheral vision loss.
Choroidal osteoma
Choroidal osteoma: rare benign ossifying choroidal tumor of mature bone, typically juxtapapillary, in young females (median age 20); diagnosed clinically with ultrasound and CT, managed by observation and anti-VEGF for neovascularization.
Choroidal rupture
Choroidal rupture: a traumatic break in Bruch's membrane, choriocapillaris, and RPE after blunt ocular trauma (ICD-11 NA06.61). Direct or indirect (countercoup) forms; main complication choroidal neovascularization treated with anti-VEGF.
Choroideremia
Choroideremia, also called progressive tapetochoroidal dystrophy (TCD), is an X-linked recessive retinal degeneration caused by CHM gene mutations, causing childhood night blindness, tunnel vision, and late blindness in males.
Chow Chow (松狮犬)
Chow Chow (松狮犬), an ancient Chinese spitz-type dog breed in FCI Group 5, known for its blue-black tongue, lion's-mane ruff, stilted gait, and aloof, dignified temperament; 17-20 inches tall, 45-70 pounds.
Choy sum (菜心)
Choy sum (菜心, caixin), Brassica rapa var. parachinensis or Chinese flowering cabbage, is an Asian brassica grown for tender flowering stems; cool-season crop, 30–50 day harvest, rich in folate and vitamin C.
CHRD
CHRD (chordin) is a human gene at 3q27.1 encoding a 955-aa secreted BMP antagonist with four vWF-C and four CHRD domains, cleaved by Tolloid, essential to dorso-ventral patterning.
Chris A. Kaiser
Chris A. Kaiser is an American cell biologist who studied protein folding in yeast at MIT, chaired its biology department from 2004, and became provost in 2012.
Chris Beyrer
Chris Beyrer is an American epidemiologist known for HIV/AIDS and COVID-19 research, director of the Duke Global Health Institute since 2022 and former president of the International AIDS Society.
Chris Boshoff
Chris Boshoff is a South African-born physician-scientist who made foundational discoveries on Kaposi's sarcoma-associated herpesvirus, founded the UCL Cancer Institute, and became Pfizer's Chief Scientific Officer in 2025.