PCNT and microcephalic osteodysplastic primordial dwarfism type II: Importantly, we found that two mutations in the PCNT gene, K3154del mutation within the PACT domain and R2918X truncate mutation, which are responsible for microcephalic osteodysplastic primordial dwarfism type 2 (MOPD2) disease29,30, drastically reduced the binding to Cep57, compared to wild-type PCNT (Fig. 5a–c).