Katherine Siminovitch and colleagues show that mice expressing the autoimmune disease–associated Ptpn22 coding variant show thymic and splenic enlargement and lymphocyte and dendritic cell hyperresponsiveness. They further show that the variant promotes degradation of the protein, suggesting that it enhances autoimmune disease risk through a loss-of-function mechanism.
- Jinyi Zhang
- Naima Zahir
- Katherine A Siminovitch
