PTS and Alport syndrome: Other examples of mutations that lead to Alu exonization include a collagen, type IV, alpha 3 (Goodpasture antigen) (COL4A3) allele causing Alport syndrome (Knebelmann et al., 1995); a survivin allele (baculoviral IAP repeat containing 5 (BIRC5)) causing Sly syndrome (Mola et al., 2007); a fibroblast growth factor receptor 2 (FGFR2) allele causing Apert syndrome (Oldridge et al., 1999); and a 6-pyruvoyltetrahydropterin synthase (PTS) allele resulting in tetrahydrobiopterin deficiency (Meili et al., 2009).