Unconventional myosin-VIIa (MYO7A)

Unconventional myosin-VIIa is a critical actin-dependent motor protein encoded by the MYO7A gene, primarily functioning in the specialized sensory cells of the inner ear and the retina. In the cochlea and vestibule, it is essential for the proper development, morphogenesis, and maintenance of the actin-rich stereocilia bundles that mediate hearing and balance. Within the eye, it facilitates the intracellular transport of melanosomes and phagosomes in the retinal pigment epithelium (RPE) and assists in the trafficking of opsins and other proteins through the connecting cilium of photoreceptors. Mutations in the MYO7A gene are the most common cause of Usher syndrome type 1B (USH1B), a condition resulting in congenital profound deafness and progressive blindness. Because of its large genetic size, therapeutic development has focused on innovative gene delivery methods such as lentiviral vectors and dual-AAV systems to overcome the packaging limits of standard viral vectors. Restoring MYO7A function remains a primary therapeutic objective for preventing the onset of retinitis pigmentosa and stabilizing sensory function in affected patients.

Other names

Myosin VIIAMYO7AUSH1BDFNB2DFNA11Myosin-7ANSRD2

Gene replacement therapy or gene augmentation therapy, where a functional copy of the MYO7A gene is delivered to target cells (e.g., RPE, photoreceptors, or hair cells) to restore protein expression and cellular function.