PPARGC1B and age-related macular degeneration: However, PGC‐1α can be, at least in part, replaced by its analogue, PGC‐1β, so apart from PGC‐1α knockout, PGC‐1β and PGC‐1α/PGC‐1β knockouts should also be used to completely assess the role of the PGC‐1 family in AMD pathogenesis.44