PAX9 and Global developmental delay: Two RO have been identified in the 14q12q21.1 interval: a proximal region (RO1, including FOXG1, NKX2‐1, and PAX9), spanning from 28,000,000 to 35,000,000, associated to severe developmental delay and poor prognosis, and a distal region (RO2, including only NKX2‐1 and PAX9), spanning from 35,000,000 to 40,000,000, associated to a milder phenotype with quite normal psychomotor development (Gentile et al., 2016; Santen et al., 2012; Figure 1D).