p53Δ31/Δ31 mice phenocopied syndromes of defective telomere maintenance in a single mouse generation, which suggested that p53 had pleiotropic effects on telomeres, and consistent with this, p53 was found to downregulate three genes mutated in dyskeratosis congenita and one gene implicated in aplastic anemia. The gene discussed is TP53; the disease is idiopathic aplastic anemia.