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LAMA3 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

LAMA3 gene

The LAMA3 gene is essential for skin integrity and wound healing, providing instructions for a key component of the basement membrane.

Normal Function

The LAMA3 gene provides instructions for the alpha subunit of laminin 332 (formerly laminin 5). Laminins are proteins that regulate cell growth, motility, and adhesion, and are vital for the organization of basement membranes—the structures that separate and support cells in various tissues.

Laminin 332 is a major component of anchoring filaments, which connect the layers of the basement membrane beneath the epidermis (the top layer of skin). This connection provides skin with strength, resiliency, and a protective barrier. Laminin 332 also plays roles in early wound healing, corneal health, and tooth enamel development. The alpha subunit produced by LAMA3 is also a component of other laminins (laminin 311 and 321) that contribute to skin strength and cell signaling.

Health Conditions Related to Genetic Changes

Junctional epidermolysis bullosa (JEB)

At least 50 mutations in the LAMA3 gene are linked to junctional epidermolysis bullosa, a condition where the epidermis is weakly connected to underlying skin layers, causing blisters from minor friction.

  • JEB generalized severe: Typically caused by mutations that prevent the production of functional laminin 332, leading to widespread, life-threatening blistering.
  • JEB generalized intermediate: Caused by mutations that allow for the production of a partially functional laminin 332 protein, resulting in milder blistering limited to areas like the hands, feet, knees, and elbows.

Laryngo-onycho-cutaneous (LOC) syndrome

LOC syndrome is a rare disorder caused by specific mutations in the LAMA3 gene that affect the alpha-3a subunit. It is characterized by:

  • Chronic skin ulcers.
  • Widespread formation of granulation tissue (red, bumpy patches).
  • Vision loss and airway blockage due to tissue buildup.
  • Malformed nails and abnormal teeth.

These mutations prevent laminin 332 from effectively attaching the epidermis to underlying layers or regulating wound healing, leading to the characteristic skin ulceration and tissue overgrowth.

Frequently Asked Questions

JEB due to LAMA3 mutations typically presents with blisters that appear within hours of minor friction, often affecting mucous membranes and leading to painful oral ulcerations. Skin biopsy with immunofluorescence mapping shows absent or reduced laminin 332 staining, confirming the diagnosis. How is wound healing managed in patients with LAMA3‑related skin fragility?::Careful wound care is essential: use non‑adhesive dressings, keep the area moist, and avoid mechanical trauma. Topical agents that promote epithelialization, such as growth factor creams, may be used under dermatology supervision. What are the key features of laryngo‑onycho‑cutaneous (LOC) syndrome, and how is it treated?::LOC syndrome presents with chronic skin ulcers, extensive granulation tissue, vision loss, and nail abnormalities. Management focuses on controlling ulceration with wound care, using systemic steroids or immunomodulators for inflammation, and addressing ocular complications with ophthalmology referral. Can genetic testing for LAMA3 variants help predict the severity of skin blistering in a newborn?::Yes, certain mutations correlate with severe generalized JEB, while others allow partial laminin 332 function, leading to milder, localized blistering. Identifying the specific variant can guide prognosis, anticipate complications, and tailor supportive care.
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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