GLA and Fabry disease: There are four investigational AAV gene therapy products currently being evaluated as potential treatments for Fabry disease: Sangamo’s ST-920 product using AAV6 capsid carrying human GLA transgene [37], uniQure’s AMT-191 using AAV5 capsid carrying a GLA transgene [38], 4D Molecular Therapeutics’ 4D-310 using a cardiac-directed capsid (C102) carrying a GLA transgene under the control of a ubiquitous promoter [39], and our synthetic AAVS3 capsid with codon-optimized human GLA cDNA under the control of the liver-specific promoter FRE1 (FLT190).