ATR and microcephalic primordial dwarfism: CFSs are under the crucial surveillance of the DNA damage-sensing kinase ATR (Mec1 in budding yeast) (Casper et al., 2002, Cha and Kleckner, 2002), mutated in Seckel syndrome and also characterized by primordial dwarfism (O’Driscoll et al., 2003).