Traits

Traits linked to COL17A1

collagen type XVII alpha 1 chain

The Human Phenotype Ontology links 63 traits to COL17A1, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the integument

Trait	How often it is seen
Abnormal blistering of the skin	Always
Lamina lucida cleavage	Always
Macular hyperpigmented dermopathy	Always
Patchy baldness	Always
Poor fingernail formation	Always
Poor nail formation	Always
Abnormal skin pigmentation	Very often (80–99%)
Absence of part of skin at birth	Very often (80–99%)
Fragile skin	Very often (80–99%)
Milk spot	Very often (80–99%)
Sparse body hair	Very often (80–99%)
Sunken or indented skin due to damage	Very often (80–99%)
Absent nails	Often (30–79%)
Acral blistering	Often (30–79%)
Adermatoglyphia	Often (30–79%)
Atrophic, patchy alopecia	Often (30–79%)
Limited armpit hair	Often (30–79%)
Skin detachment	Often (30–79%)
Sparse pubic hair	Often (30–79%)
Excessive sweating	Sometimes (5–29%)
Hypoplastic dermoepidermal hemidesmosomes	Sometimes (5–29%)
Localized skin lesion	Sometimes (5–29%)
Poor toenail formation	Sometimes (5–29%)
Atypical scarring of skin	Rarely (1–4%)
Basal cell carcinoma	Not recorded
Brittle nails	Not recorded
Cutaneous melanoma	Not recorded
Genital blistering	Not recorded
Keloids	Not recorded
Squamous cell carcinoma	Not recorded

Abnormality of the eye

Trait	How often it is seen
Corneal dystrophy	Very often (80–99%)
Eye pain	Very often (80–99%)
Progressive loss of vision	Very often (80–99%)
Recurrent breakdown of clear protective layer of eye	Very often (80–99%)
Subepithelial corneal opacities	Very often (80–99%)
Blurred vision	Often (30–79%)
Corneal scarring	Often (30–79%)
Extreme sensitivity of the eyes to light	Often (30–79%)
Irregular astigmatism	Often (30–79%)
Increased tears	Sometimes (5–29%)
Abnormality of the eye	Not recorded
Damage to outer layer of the cornea of the eye	Not recorded
Visual impairment	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Dental cavities	Always
Dental enamel pits	Always
Hair loss on scalp from scarring condition	Always
Thin dental enamel	Always
Oral mucosal blisters	Very often (80–99%)
Abnormality of dental color	Often (30–79%)
Dry eye syndrome	Sometimes (5–29%)
Abnormality of the scalp	Not recorded
Failure of development of between one and six teeth	Not recorded

Abnormality of limbs

Trait	How often it is seen
Thickening of palms and soles	Sometimes (5–29%)
Mitten deformity	Rarely (1–4%)
Excessive sweating of hands	Not recorded
Permanent flexion of the finger	Not recorded
Plantar hyperkeratosis	Not recorded

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Low number of red blood cells or hemoglobin	Often (30–79%)

Abnormality of the digestive system

Trait	How often it is seen
Gastrointestinal inflammation	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Urinary tract abnormalities	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Limb contractures	Rarely (1–4%)

Abnormality of the respiratory system

Trait	How often it is seen
Abnormal respiratory system morphology	Not recorded

Growth abnormality

Trait	How often it is seen
Growth delay	Sometimes (5–29%)

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 COL17A1 and how often each is seen. Find out more at hpo.jax.org.

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