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Focal facial dermal dysplasia
Focal facial dermal dysplasia (FFDD), also called Brauer or Setleis syndrome types, is a rare genetic ectodermal dysplasia with congenital bitemporal or preauricular scar-like facial lesions, four subtypes, TWIST2 and CYP26C1 genes known.
Focal myoclonus
Focal myoclonus (ICD-11 8A06.2) is sudden involuntary jerking of a muscle or muscle group in a localized body area, of cortical, subcortical, spinal, or peripheral origin, diagnosed by EEG-EMG neurophysiology.
Focal myositis
Focal myositis (focal nodular myositis, inflammatory pseudotumor of skeletal muscle) is a rare, benign, localized inflammation of a single skeletal muscle, usually in the lower limb, presenting as a mass that typically regresses spontaneously; biopsy confirms diagnosis.
Focal segmental glomerulosclerosis
Focal segmental glomerulosclerosis (FSGS), also called segmental glomerulosclerosis or focal sclerosis with hyalinosis, is a podocyte-injury kidney disease causing scarring in parts of some glomeruli; it causes about 20% of childhood and 40% of adult nephrotic syndrome and is classified as primary, genetic, or secondary.
Focal seizure
Focal seizure (focal onset seizure): an epileptic seizure starting in networks limited to one brain hemisphere. Under the ILAE 2025 classification, types are focal preserved consciousness, focal impaired consciousness, and focal-to-bilateral tonic-clonic; consciousness replaces awareness as classifier; affects over 60% of people with epilepsy.
Focetria
Focetria, also called influenza vaccine H1N1v, was a Novartis (later Seqirus) MF59-adjuvanted pandemic H1N1 2009 vaccine from Siena, Italy; EU-authorized 2010, expired 2015, no narcolepsy signal.
Focus reduction neutralization assay
The focus reduction neutralization assay (FRNT), or focus reduction neutralization test, is a serological assay measuring neutralizing antibodies against viruses such as dengue and SARS-CoV-2.
Focused assessment with sonography for trauma
Focused assessment with sonography for trauma (FAST), also called eFAST in extended form, is a rapid bedside ultrasound protocol detecting free fluid, typically blood, in injured patients.
Focused ultrasound
Focused ultrasound, also known as focused ultrasound surgery, directs intersecting ultrasound beams through intact skin to ablate tissue, open the blood–brain barrier, or modulate neural activity.
Focusing (psychotherapy)
Focusing (psychotherapy): experiential method by Eugene Gendlin, from 1950s research with Carl Rogers at University of Chicago; attends to the bodily felt sense via six steps from his 1978 book, basis of Focusing-Oriented Therapy.
Fodder
Fodder, also called stock feed or animal fodder, is plant material grown and harvested specifically to feed domestic animals, most commonly cattle, horses, sheep, and goats.
FODEPOC study
FODEPOC (NCT05853081) is a Spanish observational cohort study at Hospital General Universitario Gregorio Marañón testing whether the FODE scale, replacing BMI with fat-free mass index in the BODE index, better predicts COPD exacerbations and mortality.
FODMAP
FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, polyols) are poorly absorbed short-chain carbohydrates; the Monash-developed low FODMAP diet treats IBS via elimination, reintroduction, and personalization phases, with RR 0.69 for global symptoms.
Foie gras controversy
Foie gras controversy: dispute over force-feeding (gavage) of mulard ducks and geese for fatty liver. EFSA 2023 says all foie gras husbandry systems should be avoided; France protects it as heritage; bans exist in California, NYC, Portland, Brookline, and Brazil.
Foix-Chavany-Marie syndrome
Foix-Chavany-Marie syndrome (FCMS), or bilateral anterior opercular syndrome, is a rare pseudobulbar palsy with anarthria, facio-pharyngo-glosso-masticatory paralysis, and preserved automatic movements, usually from bilateral opercular strokes.
FokI
FokI, from Flavobacterium okeanokoites, is the archetype type IIS restriction endonuclease: it binds 5′-GGATG-3′, cuts 9/13 bp downstream via a dimerizing C-terminal cleavage domain, and powers ZFNs, TALENs, and dCas9-FokI editors.
Folate
Folate (vitamin B9) is a water-soluble B vitamin, also called folacin, needed for DNA synthesis and one-carbon metabolism. Folic acid is its synthetic form; 400 mcg daily periconceptionally prevents neural tube defects.
Folate deficiency
Folate deficiency (folic acid, vitamin B9 deficiency): low blood folate causing megaloblastic anemia; causes include poor diet, alcohol, malabsorption, and drugs; preventable with 400 µg daily and grain fortification.
Folate receptor
Folate receptor: cell surface glycoprotein (FRα, FRβ, FRγ, FRδ) binding folic acid with nanomolar affinity, GPI-anchored, overexpressed 100–300-fold in epithelial cancers; target for folate-conjugated drug delivery and pafolacianine tumor imaging.
Folate-derived coenzyme biosynthesis
Folate-derived coenzyme biosynthesis is the pathway that reduces folate to tetrahydrofolate via DHFR and loads it with one-carbon units, mainly from serine, producing the storage form 5-methyl-THF.
Fold recognition
Fold recognition, also known as protein fold recognition, is a protein structure prediction method that assigns a sequence to the known fold it most likely adopts by threading it through template structures.
Foley catheter
Foley catheter, indwelling urinary catheter with an inflatable balloon tip, introduced by Frederic Foley in 1935; two-channel design for bladder drainage, used in 15-25% of hospitalized patients, main risks CAUTI and noninfectious complications.
FOLFIRI
FOLFIRI is a cyclic intravenous chemotherapy regimen combining irinotecan, fluorouracil, and leucovorin, repeated every 14 days, used mainly as first-line treatment for metastatic colorectal cancer.
FOLFIRINOX
FOLFIRINOX is a four-drug chemotherapy regimen combining folinic acid, fluorouracil, irinotecan, and oxaliplatin, used first-line for metastatic pancreatic cancer, where it outperformed gemcitabine, and in modified form after resection.
FOLFOX
FOLFOX (Oxaliplatin de Gramont, OxMdG) is a combination chemotherapy regimen of leucovorin, fluorouracil, and oxaliplatin used to treat colorectal cancer, established as adjuvant standard for stage III colon cancer by the MOSAIC trial.
FOLFOX chemotherapy
FOLFOX, also known as Oxaliplatin de Gramont or OxMdG, is a combination chemotherapy regimen of folinic acid, fluorouracil, and oxaliplatin, used mainly to treat colorectal cancer.
FOLFOXIRI
FOLFOXIRI is a combination chemotherapy regimen pairing infusional fluorouracil with leucovorin, oxaliplatin, and irinotecan in two-weekly cycles, used mainly as first-line treatment for metastatic colorectal cancer.
FOLH1
FOLH1 (folate hydrolase 1), also called PSMA, GCPII, or NAALADase, is a chromosome 11 gene encoding a 750-aa transmembrane enzyme that digests dietary folates and NAAG, is upregulated in prostate cancer and IBD, and is the target of PSMA-PET imaging and Pluvicto radioligand therapy.
Folie à deux
Folie à deux, or shared psychotic disorder, is a rare condition in which delusions are transmitted from an inducer to a close associate. Also called induced delusional disorder; subtypes include folie imposée, communiquée, simultanée, and induite.
Folinic acid
Folinic acid (leucovorin calcium, citrovorum factor), 5-formyltetrahydrofolate, a reduced folate used for methotrexate rescue, 5-FU modulation in FOLFOX/FOLFIRI, and, since March 2026, the first approved treatment for FOLR1 cerebral folate transport deficiency, not autism.