Taken together, these data indicate that that p533KR/3KRXrcc4−/− mice, unlike p53−/−Xrcc4−/− mice, do not succumb to pro-B-cell lymphomas but have a short life span and exhibit aging-associated kyphosis and testicular atrophy at the age of 22 weeks. The gene discussed is TP53; the disease is Testicular atrophy.