PRPH2

PRPH2

PRPH2 (Peripherin 2) is a protein encoded by the PRPH2 gene in humans. It is a crucial component of the photoreceptor cells in the retina, playing a significant role in the structure and function of the outer segment discs of these cells. Mutations in the PRPH2 gene are associated with various retinal degenerative diseases, including retinitis pigmentosa and macular degeneration.

Structure

The PRPH2 gene is located on chromosome 6 at the 6p21.1 locus. The protein product, peripherin 2, is a transmembrane glycoprotein that is primarily found in the outer segments of rod and cone photoreceptor cells. It is a member of the tetraspanin family, characterized by four transmembrane domains, two extracellular loops, and cytoplasmic N- and C-termini.

Function

Peripherin 2 is essential for the morphogenesis and stabilization of the photoreceptor outer segment discs. These discs are critical for phototransduction, the process by which light is converted into electrical signals in the retina. Peripherin 2 interacts with other proteins, such as ROM1, to form a complex that maintains the structural integrity of the disc membranes.

Clinical Significance

Mutations in the PRPH2 gene can lead to a variety of retinal dystrophies. These include:

• Retinitis Pigmentosa (RP): A group of inherited disorders characterized by progressive peripheral vision loss and night vision difficulties, eventually leading to central vision loss.
• Pattern Dystrophy: A group of disorders with characteristic patterns of pigment deposition in the retina, often leading to central vision loss.
• Adult-onset Vitelliform Macular Dystrophy (AVMD): A condition characterized by yellowish lesions in the macula, leading to central vision impairment.

The phenotypic expression of PRPH2 mutations can vary widely, even among individuals with the same mutation, indicating the influence of other genetic and environmental factors.

Research and Therapeutic Approaches

Research into PRPH2-related diseases is ongoing, with efforts focused on understanding the molecular mechanisms underlying these conditions and developing potential therapies. Gene therapy, stem cell therapy, and pharmacological approaches are being explored as potential treatments for retinal degenerations associated with PRPH2 mutations.

Also see

• Retinitis Pigmentosa
• Photoreceptor Cells
• Tetraspanin
• Gene Therapy