PCNA and Beckwith-Wiedemann syndrome: In contrast, the clinical symptoms of patients with IMAGe syndrome strongly suggest that mutations in their CDKN1C gene are associated with gain-of-function of the CDKN1C protein, although disruption of PCNA binding and suppression of CDKN1C monoubiquitination do not directly correlate with the CDKN1C gain-of-function [9], and truncation mutants of CDKN1C lacking PCNA binding were also identified in BWS patients (Figure 1A) [11], [12].