 DALLAS--BUSINESS WIRE--Taysha Gene Therapies, Inc. Nasdaq: TSHA, a patient-centric, pivotal-stage gene therapy company focused on developing and commercializing AAV-based gene therapies for the treatment of monogenic diseases of the central nervous system CNS in both rare and large patient populations, today announced that it has been granted orphan drug designation from the European Commission for TSHA-101, an AAV9-based bicistronic gene replacement therapy in development for GM2 ganglio 