Patients of over 40 years of age have been diagnosed with compound heterozygosity for a LIG4 mutation, which can cause myelodysplasia.47 An adult patient with a homozygous congenital DNA ligase 4 mutation and non-EBV-associated DLBCL has also been reported.30 A 27-year-old woman with bilateral breast cancer and myelodysplasia was compound heterozygous for both an intronic mutation and a functional polymorphism of DCLRE1C. 48 This illustrates that patients with inherited mutations in LIG4 and DCLRE1C are not solely encountered by pediatric hematologists. The gene discussed is LIG4; the disease is breast cancer.