- Iroquois Homeobox Protein 3 (IRX3)
- Iroquois Homeobox Protein 4 (IRX4)
- Iroquois Homeobox Protein 5 (IRX5)
- Iroquois Homeobox Protein 6 (IRX6)
- Iroquois Homeobox Protein 2 (IRX2)
- Iroquois Homeobox Protein 1 (IRX1)
- Iron Responsive Element Binding Protein 2 (IREB2)
- Inositol-1,3,4,5,6-Pentakisphosphate-2-Kinase (IPPK)
- Intracisternal A Particle Promoted Polypeptide (IPP)
- Insulin Promoter Factor 1 (IPF)
- Integrator Complex Subunit 3 (INTS3)
- Integrator Complex Subunit 4 (INTS4)
- Integrator Complex Subunit 5 (INTS5)
- Integrator Complex Subunit 6 (INTS6)
- Integrator Complex Subunit 7 (INTS7)
