Traits

Traits linked to COL4A1

collagen type IV alpha 1 chain

The Human Phenotype Ontology links 110 traits to COL4A1, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the nervous system

Trait	How often it is seen
Hyperintensity of cerebral white matter on MRI	Always
Leukoencephalopathy	Always
Abnormal cerebellar vermis morphology	Very often (80–99%)
Abnormal cortical gyration	Very often (80–99%)
Abnormality of neuronal migration	Very often (80–99%)
Absent reflexes	Very often (80–99%)
Cavity within brain	Very often (80–99%)
Decreased reflex response	Very often (80–99%)
Fewer and broader ridges in brain	Very often (80–99%)
Fewer or absent grooves in brain	Very often (80–99%)
Global developmental delay	Very often (80–99%)
Intellectual disability	Very often (80–99%)
More grooves in brain	Very often (80–99%)
Small cerebellum	Very often (80–99%)
Specific learning disability	Very often (80–99%)
Too much cerebrospinal fluid in the brain	Very often (80–99%)
Ventriculomegaly	Very often (80–99%)
Abnormal periventricular white matter morphology	Often (30–79%)
Absent septum pellucidum	Often (30–79%)
Agenesis of corpus callosum	Often (30–79%)
Balance impairment	Often (30–79%)
Cognitive impairment	Often (30–79%)
Migraine with aura	Often (30–79%)
Weakness of one side of body	Often (30–79%)
Babinski sign	Sometimes (5–29%)
Dementia	Sometimes (5–29%)
Dystonia	Sometimes (5–29%)
Epilepsy	Sometimes (5–29%)
Paralysis on one side of body	Sometimes (5–29%)
Seizure affecting one half of brain	Sometimes (5–29%)
Cortical dysplasia	Not recorded
Degeneration of cerebellum	Not recorded
Focal cortical dysplasia	Not recorded
Limb dystonia	Not recorded
Migraine	Not recorded
Schizencephaly	Not recorded
Tetraparesis	Not recorded

Abnormality of the eye

Trait	How often it is seen
Breakdown of light-sensitive cells in back of eye	Very often (80–99%)
Chorioretinal dysplasia	Very often (80–99%)
Optic atrophy	Very often (80–99%)
Optic nerve issue	Very often (80–99%)
Retinal detachment	Very often (80–99%)
Retinal dysplasia	Very often (80–99%)
Abnormally small eyeball	Often (30–79%)
Absence of eyeballs	Often (30–79%)
Corneal opacity	Often (30–79%)
Extreme sensitivity of the eyes to light	Often (30–79%)
Glaucoma	Often (30–79%)
Cat eye	Sometimes (5–29%)
Clouding of the lens of the eye	Sometimes (5–29%)
Cornea of eye less than 10mm in diameter	Sometimes (5–29%)
Ocular anterior segment dysgenesis	Sometimes (5–29%)
Astigmatism	Rarely (1–4%)
Clouding of the lens of the eye at birth	Rarely (1–4%)
Decreased clarity of vision	Rarely (1–4%)
Displaced pupil	Rarely (1–4%)
Farsightedness	Rarely (1–4%)
Multiple pupils	Rarely (1–4%)
New blood vessel formation in cornea	Rarely (1–4%)
Peripapillary atrophy	Rarely (1–4%)
Underdeveloped iris	Rarely (1–4%)
Blurred vision	Not recorded
Close sighted	Not recorded
Fundus hypopigmentation	Not recorded
Lazy eye	Not recorded
Outward facing eye ball	Not recorded
Partial loss of field of vision	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Retinal arteriolar tortuosity	Always
Big calvaria	Often (30–79%)
Dandy-Walker malformation	Often (30–79%)
Retinal arterial tortuosity	Often (30–79%)
Abnormally small head	Sometimes (5–29%)
Bifid uvula	Sometimes (5–29%)
Cleft palate	Sometimes (5–29%)
Submucous cleft hard palate	Sometimes (5–29%)
Facial paralysis	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Dilation of Virchow-Robin spaces	Always
Retinal vascular tortuosity	Very often (80–99%)
Brain aneurysm	Often (30–79%)
Lacunar stroke	Often (30–79%)
Raynaud phenomenon	Often (30–79%)
Supraventricular arrhythmia	Often (30–79%)
Abnormal heart rate	Sometimes (5–29%)
Ischemic stroke	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Renal failure	Very often (80–99%)
Multiple kidney cysts	Often (30–79%)
Underdeveloped penis	Often (30–79%)
Undescended testes	Often (30–79%)
Chronic kidney disease	Sometimes (5–29%)
Cystic kidney disease	Sometimes (5–29%)
Decreased glomerular filtration rate	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Muscle spasm	Always
Absent/small skeletal muscles	Very often (80–99%)
Low muscle tone	Very often (80–99%)
Muscle degeneration	Very often (80–99%)
Muscle weakness	Very often (80–99%)
Muscular dystrophy	Very often (80–99%)
Involuntary muscle stiffness, contraction, or spasm	Not recorded

Laboratory abnormality

Trait	How often it is seen
Elevated blood creatine phosphokinase	Always
Abnormal circulating aldolase concentration	Very often (80–99%)
Abnormal circulating lactate dehydrogenase concentration	Very often (80–99%)
Abnormal levels of creatine kinase in blood	Very often (80–99%)
Blood in urine	Often (30–79%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Bleeding in brain	Often (30–79%)
Retinal bleeding	Often (30–79%)
Hemolytic anemia	Not recorded

Abnormality of the ear

Trait	How often it is seen
Ears rotated toward back of head	Sometimes (5–29%)
Low-set ears	Sometimes (5–29%)
Prominent ear	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Metatarsus valgus	Very often (80–99%)

How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the traits linked to COL4A1 and how often each is seen. Find out more at hpo.jax.org.

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