ERCC6 and Cowden syndrome 1: The abovementioned data seem to indicate that the ERCC6-related CS represents a spectrum ranging from very severe to milder forms in which the clinical characterization remains important from a diagnostic (i.e., easier clinical recognition of severe form vs. more difficult clinical recognition of milder forms) and prognostic point of view, since earlier CS II forms appear to have the most severe involvement and the worse outcome, while the outcome for milder CS III forms remains unclear, given the limited number of reported patients and poor long-term follow-up data.