4D Molecular Therapeutics is a clinical-stage gene therapy company. The company is focused on developing transformative gene therapy products for patients suffering from serious unmet medical conditions. 4D Molecular Therapeutics is developing a proprietary adeno-associated virus (AAV) gene therapy platform, which it believes has the potential to overcome the significant limitations of current gene therapy technologies. The company's lead product candidate, 4D-125, is being developed for the treatment of X-linked retinitis pigmentosa (XLRP), a rare genetic disease that causes progressive vision loss and blindness. 4D Molecular Therapeutics is headquartered in South San Francisco, California.