UGT2B17 and posterior cortical atrophy: Whereas alternative transcripts n2, n3 and n4 all code for the full-length UGT2B17 enzyme as does the canonical transcript v1, they include an additional 5′ exon, suggesting a regulation of their expression by alternative promoters (P2 and P3) rather than by the proximal promoter P1 in PCa (Fig. 4).