1,527 articles
Helicoid peripapillary chorioretinal degeneration
Helicoid peripapillary chorioretinal degeneration (Sveinsson chorioretinal atrophy, atrophia areata) is a rare autosomal dominant TEAD1-related retinal dystrophy with bilateral wing-shaped chorioretinal atrophy radiating from the optic disc, onset in infancy, sometimes with congenital anterior polar cataracts.
Hemangioblastoma
Hemangioblastoma: benign WHO grade 1 vascular tumor of the CNS, mostly cerebellum and spinal cord; sporadic or von Hippel-Lindau (VHL)-associated; treated by resection or stereotactic radiosurgery.
Hemiballism
Hemiballism (hemiballismus), the most severe form of chorea, causes violent one-sided flinging limb movements from contralateral basal ganglia lesions, classically the subthalamic nucleus though most lesions lie elsewhere; stroke and nonketotic hyperglycemia are leading causes.
Hemichorea
Hemichorea, also called hemichorea-hemiballismus, is unilateral chorea on one side of the body, classically linked to contralateral subthalamic nucleus lesions but usually caused by stroke or non-ketotic hyperglycemia.
Hemichorea or hemiballismus
Hemichorea or hemiballismus (hemichorea-hemiballism, HCHB), ICD-11 8A01.2: unilateral involuntary choreic or flinging proximal movements from contralateral basal ganglia or subthalamic lesions, most often stroke or nonketotic hyperglycemia; treated with neuroleptics, tetrabenazine, or GPi-DBS.
Hemiconvulsion-hemiplegia-epilepsy syndrome
Hemiconvulsion-hemiplegia-epilepsy syndrome (HHE, hemiplegia-hemiconvulsion-epilepsy syndrome) is a rare childhood epilepsy syndrome: febrile hemiclonic status epilepticus, immediate permanent hemiplegia, then drug-resistant focal epilepsy within about 3 years.
Hemicrania continua
Hemicrania continua, a rare indomethacin-responsive trigeminal autonomic cephalalgia, causes continuous strictly unilateral headache with ipsilateral tearing, conjunctival injection, or agitation, diagnosed by ICHD-3 criteria and treated with indomethacin.
Hemidystonia-hemiatrophy syndrome
Hemidystonia-hemiatrophy (HD-HA) syndrome, ORPHA:306741, ICD-10 G24.8: a rare dystonia with hemidystonia and ipsilateral hemiatrophy, usually after perinatal or infantile cerebral injury, stroke, or trauma; fewer than 1 per million.
Hemifacial myohyperplasia
Hemifacial myohyperplasia (HFMH) is a rare congenital disorder of unilateral overgrowth of the facial muscles only, without bone or other organ involvement; neonatal onset, prevalence under 1 in 1,000,000, described as a syndrome by Lee et al. in 2001.
Hemifacial spasm
Hemifacial spasm (HFS), also called hemispasme facial, is a movement disorder of unilateral involuntary facial muscle contractions, usually from vascular compression of the facial nerve root exit zone; treated with botulinum toxin and curative microvascular decompression (~90% spasm freedom).
Hemimegalencephaly
Hemimegalencephaly (unilateral megalencephaly) is a rare congenital brain malformation with overgrowth of one cerebral hemisphere, causing infantile drug-resistant epilepsy, hemiparesis, and developmental delay; caused by somatic PI3K-AKT-mTOR mutations and treated with hemispherectomy.
Hemiparesis
Hemiparesis is one-sided body weakness, usually from stroke or other brain, spinal cord, or nerve lesions; milder than hemiplegia, contralateral to brain lesions, treated with rehabilitation.
Hemiparkinsonism-hemiatrophy syndrome
Hemiparkinsonism-hemiatrophy syndrome (HPHA, HP-HA syndrome) is a rare parkinsonian disorder with unilateral body atrophy and ipsilateral bradykinesia, rigidity, and tremor, onset in adolescence or adulthood, prevalence under 1 per million, and variable levodopa response.
Hemiplegia
Hemiplegia is severe or complete paralysis of one side of the body (ICD-11 MB53), usually from brain or spinal cord injury such as stroke; distinguished from hemiparesis (partial weakness), with flaccid and spastic forms.
Hereditary ATTR amyloidosis
Hereditary ATTR amyloidosis (ATTRv, hATTR) is a rare autosomal dominant TTR gene disease causing misfolded transthyretin amyloid deposits in nerves and heart, treated with stabilizers and gene-silencing drugs.
Hereditary cerebral amyloid angiopathy
Hereditary cerebral amyloid angiopathy (HCHWA), including Dutch-type APP and Icelandic-type CST3 (HCCAA) disease, is a rare autosomal dominant cerebral small vessel disease causing recurrent lobar hemorrhages, seizures, and progressive dementia in adults under 55.
Hereditary geniospasm
Hereditary geniospasm (geniospasm, hereditary chin trembling, OMIM 190100) is a rare autosomal dominant movement disorder of infancy and childhood causing involuntary mentalis-muscle myoclonus with chin and lower-lip trembling, often stress-triggered, sometimes with nocturnal tongue biting, best treated with botulinum toxin injections.
Hereditary hearing loss
Hereditary hearing loss (genetic deafness, ICD-11 AB56): hearing loss caused by inherited or new genetic variants, over 150 genes implicated, at least 40% of all hearing loss; diagnosed by gene panel testing, first gene therapy approved 2026 for OTOF-related deafness.
Hereditary hyperekplexia
Hereditary hyperekplexia (familial startle disease) is a rare disorder of glycinergic inhibition affecting the brainstem, presenting as excessive startle responses and neonatal stiffness.
Hereditary hyperferritinemia-cataract syndrome
Hereditary hyperferritinemia-cataract syndrome (HHCS), also called hereditary hyperferritinemia with cataracts, is a rare autosomal dominant FTL iron-responsive-element disorder causing early bilateral cataract and high ferritin without iron overload; venesection is harmful.
Hereditary motor and sensory neuropathy type 5
Hereditary motor and sensory neuropathy type 5 (HMSN V), also called Charcot-Marie-Tooth disease with pyramidal features, is a rare autosomal dominant axonal neuropathy combining distal weakness, pes cavus, and pyramidal signs; some families carry MFN2 mutations.
Hereditary motor and sensory neuropathy type 6
Hereditary motor and sensory neuropathy type 6 (HMSN VI, CMT6) is a rare axonal neuropathy with optic atrophy, usually caused by MFN2 mutations on chromosome 1p36.2, with SLC25A46 and PDXK recessive forms, onset at 1-10 years.
Hereditary motor and sensory neuropathy, Okinawa type
Hereditary motor and sensory neuropathy, Okinawa type (HMSN-P, 沖縄型神経原性筋萎縮症) is a rare autosomal dominant TFG-gene (c.854C>T, p.Pro285Leu) neuropathy with adult-onset proximal weakness, painful cramps, fasciculations, and distal sensory loss, mostly in Okinawan descendants.
Hereditary neuropathy with liability to pressure palsies
Hereditary neuropathy with liability to pressure palsies (HNPP) is an inherited disorder in which peripheral nerves are unusually sensitive to pressure, causing recurrent numbness and palsies.
Hereditary persistence of fetal hemoglobin-intellectual disability syndrome
Hereditary persistence of fetal hemoglobin-intellectual disability syndrome, or Dias-Logan syndrome (OMIM 617101), a rare autosomal dominant BCL11A disorder with intellectual disability, developmental delay, microcephaly, and asymptomatic fetal hemoglobin persistence.
Hereditary sensory and autonomic neuropathy due to TECPR2 mutation
Hereditary sensory and autonomic neuropathy due to TECPR2 mutation (HSAN9) is an ultra-rare autosomal recessive disorder causing developmental delay, intellectual disability, and a progressive sensory and autonomic neuropathy.
Hereditary sensory and autonomic neuropathy type 1
Hereditary sensory and autonomic neuropathy type 1 (HSAN1) is a rare inherited disorder causing loss of sensation, skin ulcers, and pain, usually beginning in adulthood.
Hereditary sensory and autonomic neuropathy type 2
Hereditary sensory and autonomic neuropathy type 2 (HSAN2), also called congenital sensory neuropathy, is a rare inherited neuropathy causing loss of pain, temperature, and touch sensation from infancy.
Hereditary sensory and autonomic neuropathy type 5
Hereditary sensory and autonomic neuropathy type 5 (HSAN5) is a rare inherited neuropathy present from birth, causing loss of pain and temperature sensation while intellect stays normal.
Hereditary sensory and autonomic neuropathy type 6
HSAN6 (HSAN VI, OMIM 614653) is a rare autosomal recessive sensory and autonomic neuropathy caused by DST (dystonin) mutations, with pain insensitivity, painless fractures, ulcers, and dysautonomia; severity ranges from lethal infancy to adult-onset forms. Distinct from the PRDM12 disorder some papers also call HSAN6.