No change. IAPs are only activated to inhibit apoptosis when themselves activated by Bcl-2.

Could develop into cancer, because there wouldn't be enough IAPs to inhibit apoptosis, therefore the cells would become immortal

Too much apoptosis, because IAPs normally bind and destroy activated caspases. If there weren't enough IAPs, then apoptosis would be allowed to progress uncontrolled

Auto-immune disorder, because IAPs are only involved in the extrinsic pathway of apoptosis. A reduction in the number of IAPs would lead to auto-reacting immune cells surviving the testing process in the thymus