Fig. 2.
Alternatively spliced isoforms of APP. The APP gene contains 19 exons. Exon 13a is not included in brain isoforms. Exons 7 and 8 can be alternatively spliced to produce APP695, APP751, and APP770. APP751 and APP770 include exon 7 (orange), which encodes a Kunitz protease inhibitor (KPI) domain. APP770 also includes exon 8 (green), which encodes an OX-2 domain.