Traits

Traits linked to COL4A4

collagen type IV alpha 4 chain

The Human Phenotype Ontology links 36 traits to COL4A4, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the eye

Trait	How often it is seen
Lenticonus	Often (30–79%)
Anterior lenticonus	Sometimes (5–29%)
Retinal flecks	Sometimes (5–29%)
Subcapsular cataract	Sometimes (5–29%)
Corneal dystrophy	Rarely (1–4%)
Recurrent breakdown of clear protective layer of eye	Rarely (1–4%)
Retina degeneration	Rarely (1–4%)
Close sighted	Not recorded
Clouding of the lens of the eye	Not recorded
Clouding of the lens of the eye at birth	Not recorded
Damage to outer layer of the cornea of the eye	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Glomerular basement membrane lamellation	Very often (80–99%)
Renal failure	Very often (80–99%)
Chronic kidney disease	Often (30–79%)
Multiple kidney cysts	Often (30–79%)
Stage 5 chronic kidney disease	Often (30–79%)
Focal segmental glomerulosclerosis	Sometimes (5–29%)
Kidney inflammation	Not recorded
Nephrotic syndrome	Not recorded
Thickened glomerular basement membrane	Not recorded
Thin glomerular basement membrane	Not recorded

Laboratory abnormality

Trait	How often it is seen
Blood in urine	Very often (80–99%)
High urine protein levels	Very often (80–99%)
Bloody urine	Sometimes (5–29%)
Small amount of blood in urine	Not recorded

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Retinal bleeding	Often (30–79%)
Low platelet count	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Hypertensive retinopathy	Sometimes (5–29%)
High blood pressure	Not recorded

Abnormality of the ear

Trait	How often it is seen
Hearing impairment	Often (30–79%)
Sensorineural hearing impairment	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Reduced epidermal collagen IV alpha 5 chain staining	Very often (80–99%)
Ichthyosis	Not recorded

Abnormal tissue mass

Trait	How often it is seen
Diffuse leiomyomatosis	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Focal retinal arteriolar constriction	Very often (80–99%)

Abnormality of the endocrine system

Trait	How often it is seen
Decreased parathyroid hormone secretion	Not recorded

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 COL4A4 and how often each is seen. Find out more at hpo.jax.org.

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