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Cone-beam computed tomography reconstruction
Cone-beam computed tomography reconstruction is the set of algorithms converting cone-beam X-ray projections into 3D voxel images, used in dental imaging since the 1990s and in image-guided radiotherapy.
Conepatus
Conepatus (hog-nosed skunks), genus of skunks in family Mephitidae named by Gray in 1837; ranges from the southern United States through Central to South America, the only skunk genus there, with a large naked rooting snout and disputed species count.
Conestat alfa
Conestat alfa (Ruconest) is a recombinant human C1 esterase inhibitor made in transgenic rabbit milk, approved in 2010 for acute hereditary angioedema attacks; dosed 50 IU/kg IV, contraindicated in rabbit allergy, withdrawn from non-US markets in 2025.
Confined Spaces
Confined spaces, also called permit-required confined spaces (permit spaces), are work areas large enough to enter but with limited egress and no continuous occupancy design. Defined by OSHA 29 CFR 1910.146 (1993) and construction Subpart AA (2015); hazards include toxic, oxygen-deficient, or flammable atmospheres and engulfment.
Confirmatory trial
A confirmatory trial is a controlled clinical trial with hypotheses pre-stated and evaluated, providing firm evidence of efficacy or safety, typically in the phase III program of drug development.
Confocal laser endomicroscopy
Confocal laser endomicroscopy, also called confocal endomicroscopy, is an endoscopic imaging method using a low-power laser to give real-time, cellular-level images of the gastrointestinal lining.
Conformal radiotherapy
Conformal radiotherapy, or 3D-CRT, is a cancer treatment that shapes each external radiation beam to the tumor's outline, lowering side effects; CT-based planning enabled it in the 1980s.
Confusional arousal
Confusional arousal, also called sleep drunkenness or Elpenor syndrome, is an NREM sleep parasomnia in which a person partially wakes confused and unresponsive, stays in bed, and later amnesic; one of three disorders of arousal with sleepwalking and sleep terrors.
Congenital achiasma
Congenital achiasma, also known as achiasmia, is a rare inherited disorder present from birth in which optic nerve fibers fail to cross, causing low vision, strabismus, and nystagmus.
Congenital adrenal hyperplasia
Congenital adrenal hyperplasia (CAH) is an autosomal recessive adrenal enzyme disorder, usually 21-hydroxylase (CYP21A2) deficiency, causing low cortisol and aldosterone with excess androgens; classic form 1 in 10,000-20,000 births, nonclassic about 1 in 1,000.
Congenital adrenal hyperplasia due to 11-beta-hydroxylase deficiency
Congenital adrenal hyperplasia due to 11-beta-hydroxylase deficiency, also called CYP11B1 deficiency, is a rare autosomal recessive form of CAH causing virilization, glucocorticoid deficiency, and hypertension.
Congenital adrenal hyperplasia due to 17-alpha-hydroxylase deficiency
17-alpha-hydroxylase deficiency (17-OHD), a rare autosomal recessive CAH from CYP17A1 mutations, causing hypertension, hypokalemia, and sexual infantilism; about 1% of CAH cases, roughly 1 in 1,000,000 births.
Congenital adrenal hyperplasia due to 3-beta-hydroxysteroid dehydrogenase deficiency
Congenital adrenal hyperplasia due to 3-beta-hydroxysteroid dehydrogenase deficiency (3βHSD2D, HSD3B2 deficiency) is a rare autosomal recessive CAH causing cortisol, aldosterone, and sex steroid deficiency, salt wasting, and ambiguous genitalia in males.
Congenital adrenal hyperplasia due to cytochrome P450 oxidoreductase deficiency
P450 oxidoreductase deficiency (PORD), a rare autosomal recessive form of congenital adrenal hyperplasia caused by biallelic POR gene mutations, combining cortisol deficiency, disordered sex development, and Antley-Bixler skeletal malformations.
Congenital agenesis of the scrotum
Congenital agenesis of the scrotum (congenital scrotal absence, ORPHA:495879) is a rare urogenital malformation with absent scrotal rugae and cryptorchid or ectopic testes; hemiscrotal agenesis is the unilateral form with intact midline raphe.
Congenital alveolar capillary dysplasia
Congenital alveolar capillary dysplasia (ACDMPV) is a rare, typically fatal developmental lung disorder of newborns, usually from FOXF1 gene variants, causing refractory hypoxemia and pulmonary hypertension; lung transplant is the only cure.
Congenital amegakaryocytic thrombocytopenia
Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare autosomal recessive bone marrow failure syndrome caused by MPL mutations, presenting at birth with severe thrombocytopenia, absent megakaryocytes, and progression to pancytopenia; HSCT is the only cure.
Congenital amputation
Congenital amputation: absence of a limb or limb segment present at birth, a transverse limb reduction defect. Prevalence about 5/10,000 live births; most often caused by amniotic bands or vascular disruption; treated with prosthetics and therapy.
Congenital amyoplasia
Congenital amyoplasia (amyoplasia congenita) is the most common, sporadic form of arthrogryposis, about 1 in 10,000 births, with symmetric contractures, extended elbows, clubfeet, and fatty-fibrous muscle replacement.
Congenital analbuminemia
Congenital analbuminemia (CAA), a rare autosomal recessive ALB-gene disorder causing absent serum albumin (<1 g/L), mild adult symptoms, hypercholesterolemia, perinatal risk, and about 1 per million prevalence.
Congenital antral web
Congenital antral web (prepyloric diaphragm, gastric antral web): a rare 2–4 mm mucosal membrane 1–7 cm proximal to the pylorus causing gastric outlet obstruction, presenting with non-bilious vomiting and failure to thrive, treated surgically or by endoscopic balloon dilation.
Congenital aortic regurgitation
Congenital aortic regurgitation (congenital aortic valve insufficiency, ICD-11 LA8A.21): incomplete aortic valve closure present at birth. Found in 1.3% of screened newborns, usually trivial, linked to bicuspid aortic valve.
Congenital aortic valve stenosis
Congenital aortic valve stenosis (ORPHA:3093, ICD-10 Q23.0): congenital narrowing of the aortic valve, usually bicuspid; 3.8-4.9 per 10,000 live births, 3-6% of congenital heart disease, male predominance, treated by balloon valvuloplasty or surgery.
Congenital aplastic anaemia
Congenital aplastic anaemia, ICD-11 3A70.0, also called constitutional or inherited aplastic anemia: antenatally determined stem cell failure causing pancytopenia, covering Fanconi anemia, dyskeratosis congenita, and familial hypoplastic anemia, but excluding congenital amegakaryocytic thrombocytopenia.
Congenital asplenia
Congenital asplenia: absence of the spleen from birth, isolated (often RPSA-related, autosomal dominant) or syndromic with heterotaxy and heart defects; marked risk of pneumococcal sepsis, managed with vaccination and penicillin prophylaxis.
Congenital ataxia
Congenital ataxia (ICD-11 8A03.0) is a group of early-onset, usually nonprogressive cerebellar ataxias with hypotonia, developmental delay, and cognitive impairment, classified into cerebellar malformation, syndromic, hypoplasia, and pontocerebellar hypoplasia forms.
Congenital atransferrinemia
Congenital atransferrinemia (congenital hypotransferrinemia), autosomal recessive TF gene disorder causing near-absent transferrin, severe microcytic anemia with iron overload; under 20 reported cases, treated with plasma or apotransferrin infusions.
Congenital autosomal recessive small-platelet thrombocytopenia
Congenital autosomal recessive small-platelet thrombocytopenia (CARST), also called thrombocytopenia 3, is a rare inherited bleeding disorder with abnormally small, few platelets from birth, caused by FYB1 gene mutations.
Congenital bilateral absence of vas deferens
Congenital bilateral absence of the vas deferens (CBAVD): absence of both vasa deferentia causing obstructive azoospermia; a CFTR-related disorder linked to cystic fibrosis mutations, also associated with ADGRG2; treated by sperm retrieval with ICSI.
Congenital bile acid synthesis defect type 1
Congenital bile acid synthesis defect type 1 (CBAS1, 3β-HSD deficiency, HSD3B7 mutations) is an autosomal recessive bile acid synthesis disorder causing neonatal cholestasis and fat malabsorption, treatable with oral cholic acid.