A Hsap\TPI1 coding sequence carrying the disease-associated I170V amino acid replacement is expressed under the control of Tpi regulatory sequences at the endogenous Tpi locus (the human coding sequence replaces the endogenous Drosophila coding sequence). The Hsap\TPI1 coding sequence has been modified to ensure expression in Drosophila (the sequence has been recoded for Drosophila codon usage and has the Drosophila intron-exon and splicing architecture). It was inserted into the Drosophila genome via phiC31:int-mediated integration into the attP site present in TpiattP.