RECQL4 and Rothmund-Thomson syndrome: While it is impossible to draw extensive conclusions regarding this hypothesis based on the data presented here, the fact remains that only about two-thirds of patients with Rothmund-Thomson syndrome have mutations in RECQL4. Given that the disease phenotype can arise independently of RECQL4 mutations, it should be reconciled whether the affected function of RECQL4 depends on another protein that is also impaired by a mutation causing the remaining third of RTS cases.