TPP1 and granular corneal dystrophy type II: We conducted a site-directed mutagenesis screen in the TIN2- and POT1-binding regions of full-length TPP1 (Figure 1B) to map new interacting regions within these proteins, discover separation-of-function mutations that disrupt only 1 binding interface of TPP1, and compare the physiological consequences of these mutations with telomeropathy-associated mutations of ACD in mouse hematopoietic stem cells.