PTPN6 and Interstitial pneumonitis: So-called “motheaten” mice have a recessive Ptpn6 frameshift mutation that leads to an absence of SHP-1 protein (Green and Shultz, 1975; Shultz et al., 1993; Tsui et al., 1993), and exhibit severe skin inflammation, as well as interstitial pneumonitis and a range of hematological abnormalities, including hyperproliferative T cells (Minton, 2013).