The transgene comprises 12.3 kb of human genomic DNA containing the GPD1 gene, consisting of 3.5 kb of 5' flanking sequence, the 7.6 kb protein-coding region and 1.2 kb of 3' flanking DNA. The 5' flanking sequence includes the proximal and distal promoter regions. Founder line A2 has approximately 14 copies of the transgene. Mice exhibit a much higher level of transgene expression in the cerebral cortex and kidney than is normal for the endogenous gene.