MYO5A gene

The MYO5A gene provides instructions for making myosin Va, a protein critical for transporting molecules within pigment-producing cells and neurons.

Normal Function

The MYO5A gene provides instructions for making a protein called myosin Va, which belongs to a group of proteins called unconventional myosins. These proteins play a role in transporting molecules within cells by using long filaments of actin as tracks.

Myosin Va is found in pigment-producing cells called melanocytes, where it helps transport structures called melanosomes. These structures produce melanin, the substance that gives skin, hair, and eyes their color. Myosin Va interacts with proteins produced from the MLPH and RAB27A genes to transport melanosomes to the outer edges of melanocytes, where they are transferred to other cells.

In the brain, myosin Va plays an important role in neurons. It transports various proteins and molecules within these cells and is involved in the release of substances from cells (exocytosis), which is critical for normal brain function.

Health Conditions Related to Genetic Changes

Griscelli syndrome

Mutations in the MYO5A gene can cause Griscelli syndrome type 1. This condition is characterized by:

• Unusually light (hypopigmented) skin
• Silvery-gray hair
• Neurological abnormalities, including delayed development, intellectual disability, and seizures

These mutations prevent the production of functional myosin Va. Without this protein, melanosomes cannot be transported to the edges of melanocytes and instead clump near the center, preventing normal pigmentation. Additionally, the loss of myosin Va in neurons disrupts the transport of molecules, leading to the neurological problems associated with the syndrome.