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KRT1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

KRT1 gene

The KRT1 gene provides instructions for making keratin 1, a protein essential for the structural integrity and resilience of the skin, hair, and nails.

Normal Function

The KRT1 gene provides instructions for making a protein called keratin 1. Keratins are a group of tough, fibrous proteins that form the structural framework of cells called keratinocytes that make up the skin, hair, and nails. Keratin 1 is produced in keratinocytes in the outer layer of the skin (the epidermis), including the skin on the palms of the hands and soles of the feet.

The keratin 1 protein partners with another keratin protein, either keratin 9 or keratin 10, to form molecules called keratin intermediate filaments. These filaments assemble into strong networks that provide strength and resiliency to the skin and protect it from being damaged by friction and other everyday physical stresses.

Health Conditions Related to Genetic Changes

Epidermolytic hyperkeratosis

Dozens of mutations in the KRT1 gene have been found in people with epidermolytic hyperkeratosis. This condition is a skin disorder characterized by red, blistering skin at an early age and thick skin (hyperkeratosis) later in life. People with KRT1 gene mutations typically have PS-type epidermolytic hyperkeratosis, which features thick skin on the palms of the hands and soles of the feet (palmoplantar hyperkeratosis) in addition to other parts of the body.

Most KRT1 gene mutations associated with epidermolytic hyperkeratosis change a single protein building block (amino acid) in the keratin 1 protein. These mutations alter the keratin 1 protein and seem to affect how intermediate filaments interact with each other to form networks. The altered proteins still form intermediate filaments, but the networks are weaker and do not function normally. Without a strong network, skin cells become fragile and are easily damaged, which can lead to blistering in response to friction or mild trauma.

Other disorders

KRT1 gene mutations are involved in many other skin disorders:

  • Epidermolytic palmoplantar keratoderma: A relatively mild condition where individuals typically have palmoplantar hyperkeratosis with detachment or loosening of the epidermis (epidermolysis), usually seen as blistering.
  • Nonepidermolytic palmoplantar keratoderma: Characterized by palmoplantar hyperkeratosis with no evidence of epidermolysis.
  • Striate palmoplantar keratoderma type 3: A condition where skin thickening on the palms and soles follows a specific pattern.
  • Curth-Macklin ichthyosis hystrix: Involves severe hyperkeratosis on the palms and soles and sometimes the skin over large joints or on the torso.
  • Cyclic ichthyosis with epidermolytic hyperkeratosis: Similar to epidermolytic hyperkeratosis, but the skin changes disappear for short periods, then recur.

Other Names for This Gene

  • 67 kDa cytokeratin
  • CK-1
  • CK1
  • cytokeratin 1
  • cytokeratin-1
  • EHK1
  • hair alpha protein
  • K1
  • K2C1_HUMAN
  • keratin 1, type II
  • keratin, type II cytoskeletal 1
  • KRT1A
  • type-II keratin Kb1

Frequently Asked Questions

Early‑onset blistering, erythema, and thickening of the skin—especially on the palms and soles—are hallmark features. The skin may appear red and fragile in infancy, then develop pronounced hyperkeratosis (thick, callus‑like plaques) later in childhood or adulthood. A family history of similar skin findings can also raise suspicion.
The diagnosis is confirmed by a skin biopsy examined under light microscopy, which shows characteristic epidermal blistering and hyperkeratosis. Genetic testing (sequencing of the KRT1 gene) can identify the specific mutation, which is useful for family counseling and confirming the diagnosis.
Topical keratolytics (e.g., urea 10–40%, salicylic acid) and emollients reduce scaling and improve skin softness. For severe hyperkeratosis, oral retinoids (e.g., acitretin) may be prescribed under close monitoring for side effects. Protective measures—such as wearing soft gloves, avoiding friction, and using moisturizers—are essential to prevent blistering and secondary infections.
Yes, keratin 1 is also expressed in hair follicles and nails, so patients may notice brittle, slow‑growing nails or hair that is fine and prone to breakage. Regular dermatologic examinations can track changes, and patients should use gentle hair care products, avoid harsh chemicals, and keep nails trimmed to reduce trauma.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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