The MLPH gene provides instructions for making a protein called melanophilin. This protein 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). Melanophilin interacts with proteins produced from the MYO5A 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.
At least one mutation in the MLPH gene has been found to cause Griscelli syndrome. This genetic change causes a form of the condition designated type 3, which is characterized by unusually light (hypopigmented) skin and silvery-gray hair. Unlike the other forms of Griscelli syndrome, type 3 does not involve abnormalities of the brain or immune system.
The known MLPH gene mutation changes a single protein building block (amino acid) in the melanophilin protein. Specifically, it replaces the amino acid arginine with the amino acid tryptophan at protein position 35 (written as Arg35Trp or R35W). This mutation reduces the amount of melanophilin produced; the small amount of protein that is produced is unable to form a complex with the proteins made from the MYO5A and RAB27A genes. Without this complex, melanosomes cannot be transported to the edges of melanocytes. Instead, they clump near the center of melanocytes, trapping melanin within these cells and preventing normal pigmentation of skin and hair.
- slp homolog lacking C2 domains a
- synaptotagmin-like protein 2a