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RAB27A gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

RAB27A gene

The RAB27A gene encodes a protein critical for vesicle trafficking in pigment-producing cells and immune system cells, playing a key role in pigmentation and infection defense.

Normal Function

The RAB27A gene provides instructions for making a protein involved in vesicle trafficking, which moves proteins and other molecules within cells in sac-like structures called vesicles. While found throughout the body, it is most critical in melanocytes (pigment-producing cells) and certain immune system cells.

  • In melanocytes: The Rab27a protein helps transport melanosomes, which produce melanin. It interacts with proteins from the MLPH and MYO5A genes to transport melanosomes to the outer edges of melanocytes, where they are transferred to other cells to provide pigment for skin, hair, and eyes.
  • In immune system cells: Rab27a is important in T-lymphocytes. It is involved in cytotoxic granule exocytosis, the process by which these cells release compounds to destroy foreign invaders like viruses and bacteria.

Health Conditions Related to Genetic Changes

Griscelli syndrome

At least 24 mutations in the RAB27A gene have been found in people with Griscelli syndrome type 2, characterized by hypopigmented skin, silvery-gray hair, and immune system abnormalities.

  • Pigmentation issues: A shortage of functional Rab27a protein impairs the transport of melanosomes. These structures clump near the center of melanocytes, trapping melanin and preventing normal skin and hair pigmentation.
  • Immune system issues: Loss of Rab27a function in T-lymphocytes impairs cytotoxic granule exocytosis, making individuals prone to recurrent infections.
  • Hemophagocytic lymphohistiocytosis (HLH): A shortage of Rab27a in immune cells can lead to HLH, a condition where the immune system produces too many activated T-lymphocytes and macrophages. This overactivity can damage organs and tissues throughout the body.

Other Names for This Gene

  • GS2
  • GTP-binding protein Ram
  • HsT18676
  • rab-27
  • RAB27
  • RAM
  • ras-related protein Rab-27A
  • RB27A_HUMAN

Frequently Asked Questions

The earliest signs often include unusually light skin pigmentation (hypopigmentation) and silvery-gray hair, which may be noticeable shortly after birth or in early infancy. Beyond these cosmetic changes, recurrent infections, prolonged fevers, or unusual bruising could signal the immune system problems associated with the syndrome, requiring immediate medical evaluation.
shortage of functional Rab27a protein in immune cells impairs their ability to properly eliminate foreign invaders. This can lead to an uncontrolled activation of T-lymphocytes and macrophages, causing them to attack the body's own tissues and organs, which is characteristic of HLH. Critical symptoms of an HLH crisis include persistent high fever, enlarged liver and spleen, low blood cell counts (anemia, thrombocytopenia), and neurological changes like seizures or irritability. These symptoms warrant urgent medical care.
For the pigmentation issues, there is currently no specific treatment to restore normal skin and hair color, but sun protection is crucial due to increased sun sensitivity. The immune system abnormalities, which can be life-threatening, are managed more aggressively. This often involves immunosuppressive therapy to control the overactive immune response and, in severe cases, hematopoietic stem cell transplantation (bone marrow transplant) to replace the faulty immune cells.
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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