CAMBRIDGE, Mass.--(BUSINESS WIRE)--Seaside Therapeutics LLC today announced that the Company has initiated a Phase 1 clinical trial of STX107, a highly potent, selective mGluR5 antagonist, in development for the treatment of Fragile X Syndrome. The single ascending dose study is designed to evaluate the safety, tolerability and pharmacokinetics of STX107 in healthy volunteers. Fragile X Syndrome is the most common inherited form of mental impairment and the most common known cause of autism.