Nervous and sensory conditions

Congenital Horner syndrome

Congenital Horner syndrome is a rare condition present from birth in which oculosympathetic nerve damage causes a constricted pupil, drooping eyelid, and often a lighter-colored iris.

Congenital hydrocephalus

Congenital hydrocephalus (ORPHA:2185, ICD-10 Q03) is in-utero ventricular enlargement from impaired CSF circulation, occurring in 0.3-2.5 per 1,000 live births, treated by shunt or ETV.

Congenital hypotonia (floppy baby syndrome, ICD-11 KB08.2) is abnormally decreased muscle tone present at birth, mostly central (60-80%) in origin; rapid exome/genome sequencing diagnoses over 50% of NICU cases.

Congenital ichthyosis-intellectual disability-spastic quadriplegia syndrome

A rare autosomal recessive syndrome, also known as ELOVL4-related neuro-ichthyosis, caused by mutations in the ELOVL4 gene and combining congenital ichthyosis with intellectual disability, infantile-onset seizures, and spastic tetraplegia.

Congenital insensitivity to pain

Congenital insensitivity to pain (CIP, congenital analgesia) is an extremely rare genetic inability to feel pain from birth, caused by genes such as NTRK1, SCN9A, and PRDM12, leading to self-mutilation, fractures, and, in CIPA/HSAN IV, anhidrosis.

Congenital insensitivity to pain syndrome, Marsili type

Marsili syndrome (MARSIS, OMIM 147430), congenital insensitivity to pain syndrome, Marsili type: rare autosomal dominant ZFHX2 (14q11.2) disorder with lowered pain, temperature, and sweat sensing; painless fractures and burns, preserved touch and visceral pain.

Congenital insensitivity to pain with anhidrosis

Congenital insensitivity to pain with anhidrosis (CIPA, HSAN type IV) is a rare autosomal recessive NTRK1 disorder causing inability to feel pain and temperature, absent sweating, recurrent fevers, self-mutilation, and intellectual disability.

Congenital limbs-face contractures-hypotonia-developmental delay syndrome

CLIFAHDD syndrome (OMIM 616266), congenital limbs-face contractures-hypotonia-developmental delay syndrome, is a rare autosomal dominant NALCN channelopathy with congenital contractures, hypotonia, respiratory distress, and developmental delay, caused by de novo missense variants.

Congenital microcephaly-severe encephalopathy-progressive cerebral atrophy syndrome

Congenital microcephaly-severe encephalopathy-progressive cerebral atrophy syndrome, or asparagine synthetase deficiency (ASNSD), is an ultrarare autosomal recessive ASNS-gene disorder causing progressive microcephaly, intractable seizures, spastic quadriplegia, and early death.

Congenital microcoria

Congenital microcoria (MCOR, congenital miosis, MIM 156600) is a rare autosomal dominant iris development disorder with bilateral pupils under 2 mm that resist dilation, linked to 13q32.1 deletions affecting TGDS and GPR180, with myopia in 80% and glaucoma in 30% of cases.

Congenital myasthenic syndrome

Congenital myasthenic syndrome (CMS, congenital myasthenia): inherited genetic disorders of neuromuscular junction signaling causing fatigable weakness from birth or childhood; over 35 genes, usually autosomal recessive, treatment tailored to genetic subtype.

Congenital oculomotor nerve palsy

Congenital oculomotor nerve palsy (congenital third cranial nerve palsy, congenital CNIII lesion) is a rare neonatal disorder causing ptosis, ophthalmoplegia, strabismus, and amblyopia, typically unilateral, often with aberrant regeneration.

Congenital optic atrophy

Congenital optic atrophy (ICD-11 9C40.B0) is optic nerve axon loss present from birth or inherited, mainly autosomal dominant optic atrophy (OPA1) and Leber hereditary optic neuropathy, distinct from optic nerve hypoplasia.

Congenital orbital cyst

Congenital orbital cyst (ICD-11 9A23.0, 先天眼窩嚢胞): developmental orbital cyst from sequestered embryonic ectoderm; commonest childhood orbital mass, mainly dermoid; six epithelial subtypes, excised surgically.

Congenital ptosis

Congenital ptosis, also called congenital blepharoptosis, is upper eyelid drooping present at birth, usually from dystrophic levator palpebrae superioris muscle. Unilateral in about 75% of isolated cases; graded by MRD1; treated with levator resection or frontalis sling; risk includes amblyopia.

Congenital retinal aneurysm

Congenital retinal aneurysm (ICD-11 LA13.5, ICD-10 Q14.1) is a rare developmental dilation of a retinal artery, distinguished from acquired macroaneurysms of hypertensive elderly patients and linked to congenital macrovessels and FRAM.

Congenital retinal arteriovenous communication

Congenital retinal arteriovenous communication (retinal racemose hemangioma, Wyburn-Mason syndrome when cerebral AVMs coexist): a rare unilateral retinal malformation with direct artery-vein shunting and no capillaries, prevalence under 1 per million, ICD-10 Q14.1.

Congenital sensorineural hearing loss

Congenital sensorineural hearing loss: permanent inner-ear or auditory-nerve hearing loss of ≥40 dB in the better ear present at birth; mostly genetic, with congenital CMV the leading non-genetic cause; treated with implants, valganciclovir, and now OTOF gene therapy.

Congenital stromal corneal dystrophy

Congenital stromal corneal dystrophy (CSCD, congenital hereditary stromal dystrophy, Witschel dystrophy, OMIM 610048) is an extremely rare autosomal dominant DCN (decorin) disorder causing bilateral flaky corneal stromal clouding from birth and moderate to severe vision loss, treated with keratoplasty.

Congenital trigeminal anesthesia

Congenital trigeminal anesthesia (ORPHA 231013, ICD-10 G50.8) is a rare neuro-ophthalmological disorder: congenital sensory deficit of the trigeminal nerve causing painless corneal ulcers, neurotrophic keratitis, and poorly healing facial wounds from infancy.

Congenital trochlear nerve palsy

Congenital trochlear nerve palsy (congenital superior oblique palsy, congenital fourth nerve palsy, ORPHA:98686): birth-present fourth cranial nerve dysfunction causing vertical strabismus, head tilt, and diplopia, often decompensating in adulthood; about 73% show trochlear nerve absence on MRI.

Conjunctival malignant melanoma

Conjunctival malignant melanoma (conjunctival melanoma, Co-M) is a rare ocular surface cancer of conjunctival melanocytes, ~0.46 cases per million yearly, arising mostly from PAM/C-MIL, treated by no-touch excision with cryotherapy, recurring or metastasizing in a quarter to a third of patients.

Convergence insufficiency

Convergence insufficiency (CI), a common binocular vision disorder in which the eyes fail to converge at near, causing eye strain, blurred or double vision, and headaches; treated most effectively with office-based vergence/accommodative vision therapy.

Convergence-retraction nystagmus

Convergence-retraction nystagmus (CRN, 輻輳後退眼振, ICD-11 9C84.52) is a nystagmus-like ocular oscillation of rapid convergent and globe-retracting movements on attempted upgaze, caused by dorsal midbrain lesions and characteristic of Parinaud syndrome.

Convulsion

Convulsion: sudden, violent involuntary muscle contractions causing rapid rhythmic shaking, also called a fit or attack; seen in tonic-clonic epileptic seizures, childhood fever, syncope, and drug or alcohol abuse.

Convulsive status epilepticus

Convulsive status epilepticus (CSE, ICD-11 8A66.0) is generalized tonic-clonic seizure activity lasting 5 minutes or more or recurring without recovery, a neurological emergency treated first with benzodiazepines, with mortality up to 30% in adults.

Coprolalia

Coprolalia: involuntary utterance of obscene or socially inappropriate words, mainly a complex vocal tic of Tourette syndrome; affects about 10-15% of patients, not required for diagnosis, also seen after stroke, encephalitis, or in frontotemporal dementia.

Corneal dystrophy-perceptive deafness syndrome

Corneal dystrophy-perceptive deafness syndrome, or Harboyan syndrome (CDPD), is a rare autosomal recessive SLC4A11 disorder combining congenital corneal endothelial dystrophy with progressive postlingual sensorineural hearing loss, OMIM 217400.

Corneal neovascularization

Corneal neovascularization: abnormal ingrowth of new blood vessels from the limbus into the normally avascular cornea, caused by hypoxia, inflammation, infection, or graft rejection; treated with steroids, anti-VEGF agents, and laser therapy.