Our results suggest that the CDC73 mutations seen in sporadic and hereditary parathyroid carcinomas and the CTR9 mutations found in Wilms tumor could cause increased genome instability; however, it is not currently known if these defects in human CDC73 and CTR9 cause genome instability and telomere dysfunction in human cells as observed here for the S. cerevisiae cdc73Δ mutation. The gene discussed is CTR9; the disease is parathyroid gland carcinoma.