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The official name of this gene is “myosin VA (heavy chain 12, myoxin).”
MYO5A is the gene's official symbol. The MYO5A gene is also known by other names, listed below.
The MYO5A gene provides instructions for making a protein called myosin Va, which is part of a group of proteins called unconventional myosins. These proteins, which have similar structures, each play a role in transporting molecules within cells. Myosins interact with actin, a protein that is important for cell movement and shape. Researchers believe that myosins use long filaments of actin as tracks along which to transport other molecules.
Myosin Va is found in pigment-producing cells called melanocytes, where it helps transport structures called melanosomes. These structures produce a pigment called melanin, which is the substance that gives skin, hair, and eyes their color (pigmentation). Myosin Va interacts with proteins produced from the MLPH and RAB27A genes to form a complex that transports melanosomes to the outer edges of melanocytes. From there, the melanosomes are transferred to other types of cells, where they provide the pigment needed for normal hair, skin, and eye coloring.
Myosin Va also plays an important role in nerve cells (neurons) in the brain. Studies suggest that myosin Va transports various proteins and other molecules within neurons. It is also involved in the release of certain substances from these cells (exocytosis). The movement of these materials appears to be critical for normal brain function.
The MYO5A gene belongs to a family of genes called myosins (myosins).
A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.
At least two mutations in the MYO5A gene have been found in people with Griscelli syndrome. These mutations cause a form of the condition designated type 1, which is characterized by unusually light (hypopigmented) skin, silvery-gray hair, and neurological abnormalities resulting in delayed development, intellectual disability, and seizures. The known MYO5A gene mutations prevent the production of functional myosin Va. Because the nonfunctional protein cannot form a complex with the proteins made from the MLPH and RAB27A genes, melanosomes cannot be transported to the edges of melanocytes. Instead, these structures clump near the center of melanocytes, trapping melanin within these cells and preventing normal pigmentation of skin and hair. A loss of myosin Va in neurons disrupts the transport of proteins and other molecules within and out of these cells, which likely causes the neurological problems found in Griscelli syndrome type 1.
Cytogenetic Location: 15q21
Molecular Location on chromosome 15: base pairs 52,307,282 to 52,529,049
The MYO5A gene is located on the long (q) arm of chromosome 15 at position 21.
More precisely, the MYO5A gene is located from base pair 52,307,282 to base pair 52,529,049 on chromosome 15.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about MYO5A helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
actin ; cell ; disability ; gene ; kinase ; melanin ; melanocytes ; myosin ; myosin heavy chain ; neurological ; pigment ; pigmentation ; protein ; syndrome
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.