1,527 articles
Fetal methylmercury syndrome
Fetal methylmercury syndrome, or congenital Minamata disease (水俣病), is prenatal brain poisoning caused when maternal seafood-borne methylmercury crosses the placenta, first certified in Japan in 1962.
Fibrosis-neurodegeneration-cerebral angiomatosis syndrome
FINCA syndrome (fibrosis, neurodegeneration, cerebral angiomatosis; OMIM 618278, ORPHA:621758) is a rare autosomal recessive NHLRC2-related infantile multisystem disorder with interstitial lung fibrosis, neurodevelopmental delay, seizures, recurrent infections, and macrocytic anemia.
Fingolimod
Fingolimod (FTY720), sold as Gilenya, is an oral sphingosine 1-phosphate receptor modulator for relapsing multiple sclerosis, approved by the FDA in 2010 as the first oral MS therapy.
Flaccid hemiplegia
Flaccid hemiplegia (ICD-11 MB53.1, ICD-10-CM G81.0) is one-sided paralysis with limp, low-tone muscles, seen acutely after cortical or internal capsule lesions and sometimes permanent.
Flaccid tetraplegia
Flaccid tetraplegia is paralysis of all four limbs with limp, toneless muscles, unlike the stiffness of spastic tetraplegia; it typically reflects lower motor neuron damage or acute spinal shock.
Flynn-Aird syndrome
Flynn-Aird syndrome (OMIM 136300, ORPHA:2047) is an ultra-rare autosomal dominant neuroectodermal disorder with childhood-onset deafness, retinitis pigmentosa, myopia, cataracts, dementia, ataxia, skin atrophy, and bone cysts, described in one family since 1965.
Focal aware seizure
Focal aware seizure (ICD-11 8A68.3), formerly simple partial seizure: a focal onset epileptic seizure with retained awareness of self and environment; 2025 ILAE revision renames it focal seizure with consciousness preserved.
Focal brain contusion
Focal brain contusion (ICD-11 NA07.4C) is a localized bruise of cerebral cortex and subcortical white matter after head trauma; it progresses in 40–50% of cases within 24 hours and is monitored by CT and MRI.
Focal brain injury
Focal brain injury (ICD-11 NA07.4) is traumatic brain damage confined to one region, usually from a direct blow or penetration: contusions, lacerations, and extradural, subdural, or intracerebral hematomas, versus diffuse injury such as diffuse axonal injury.
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 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.
Folinic acid-responsive seizures
Folinic acid-responsive seizures (FARS), also called folinic acid responsive developmental and epileptic encephalopathy, is a rare neonatal epileptic encephalopathy with myoclonic and clonic seizures with apnea, responding to folinic acid; genetically identical to pyridoxine-dependent epilepsy (ALDH7A1) or caused by FOLR1 folate transport defects.
Foreign accent syndrome
Foreign accent syndrome (FAS) is a rare motor speech disorder in which stroke, brain injury, or other neurological damage makes a person's native speech sound foreign; first described by Pierre Marie in 1907, named by Whitaker in 1982.
Fourth nerve palsy
Fourth nerve palsy, also called trochlear nerve palsy, is weakness of the cranial nerve supplying the superior oblique muscle, causing vertical double vision worse when looking down.
Foveal hypoplasia-optic nerve decussation defect-anterior segment dysgenesis syndrome
FHONDA syndrome (foveal hypoplasia-optic nerve decussation defect-anterior segment dysgenesis) is a rare autosomal recessive eye disease caused by SLC38A8 mutations, with nystagmus, chiasmal misrouting, and severe foveal hypoplasia but no albinism-related hypopigmentation.
Fragile X-associated tremor/ataxia syndrome
FXTAS (fragile X-associated tremor/ataxia syndrome) is a late-onset neurodegenerative disorder of FMR1 premutation carriers (55–200 CGG repeats), causing intention tremor, cerebellar ataxia, and cognitive decline after age 50, mainly in men.
Frequent episodic tension-type headache
Frequent episodic tension-type headache (ICHD-3 2.2) is a primary headache with bilateral, pressing, mild-to-moderate attacks on 1-14 days/month for >3 months; treated with simple analgesics and, if disabling, preventives such as amitriptyline.
Frey syndrome
Frey syndrome (auriculotemporal syndrome, gustatory hyperhidrosis): gustatory sweating and flushing from aberrant parasympathetic regeneration after auriculotemporal nerve injury, usually parotidectomy; described by Lucja Frey, 1923.
Front of the Class
Front of the Class is a 2008 Hallmark Channel TV movie directed by Peter Werner, starring James Wolk as teacher Brad Cohen, whose Tourette syndrome did not stop him from winning a Georgia teaching award.
Frontotemporal dementia with motor neuron disease
Frontotemporal dementia with motor neuron disease (FTD-MND, FTD-ALS): combined frontotemporal dementia and ALS within the ALS-FTD spectrum, onset 38-78 years, TDP-43 pathology, C9orf72 expansion, death 2-5 years after onset.
Fuchs heterochromic iridocyclitis
Fuchs heterochromic iridocyclitis, also called Fuchs uveitis syndrome (FUS), is a chronic, usually unilateral, mild anterior uveitis first described by Ernst Fuchs in 1906, marked by stellate keratic precipitates, iris atrophy, and cataract or glaucoma complications.
Full schwannomatosis
Full schwannomatosis is a rare, fully expressed form of neurofibromatosis marked by multiple benign nerve sheath tumors that usually spare the vestibular nerves and often cause severe chronic pain.
Functional tremor
Functional tremor (psychogenic tremor), the most common functional movement disorder, is involuntary-appearing tremor with variability, distractibility, and entrainment; diagnosed clinically and electrophysiologically, treated with physiotherapy and CBT.
Fundus albipunctatus
Fundus albipunctatus (OMIM 136880) is a rare autosomal recessive congenital stationary night blindness with white midperipheral retinal dots and delayed dark adaptation, usually caused by RDH5 mutations; distinct from progressive retinitis punctata albescens.
Fundus pulverulentus
Fundus pulverulentus is the rarest pattern dystrophy of the retinal pigment epithelium, first described by Slezak and Homer in 1969, marked by granular coarse RPE mottling of the macula, strong pseudoxanthoma elasticum association, and reported choroidal neovascularization.
Fungal encephalitis
Fungal encephalitis, or fungal meningoencephalitis, is brain inflammation from fungal CNS infection, most often cryptococcal in HIV and immunocompromised patients; mortality reaches 24–47% at 10 weeks despite amphotericin-based therapy.
Fungal meningitis
Fungal meningitis: rare, life-threatening fungal infection of the brain and spinal cord membranes, usually in immunocompromised people; caused by Cryptococcus, Candida, Histoplasma, Blastomyces, Coccidioides; treated with IV antifungals.
Gamma-aminobutyric acid transaminase deficiency
Gamma-aminobutyric acid transaminase deficiency, also called GABA-T or GABA transaminase deficiency, is an ultra-rare autosomal recessive ABAT-gene disorder causing neonatal epileptic encephalopathy, hypotonia, choreoathetosis, accelerated growth, and elevated CSF GABA.
Gangliocytoma
Gangliocytoma: rare WHO grade I mixed neuronal-glial CNS tumor of dysplastic ganglion cells in non-neoplastic glial stroma, mostly temporal lobe, presenting with seizures; no defined molecular signature.
Ganglioglioma
Ganglioglioma, a rare WHO grade 1 glioneuronal brain tumor of children and young adults, mixed glial and neuronal cells, temporal lobe, seizures, BRAF V600E, treated by surgical resection.