COL4A2 and Global developmental delay: Genetic variants of DIP2A, DIP2B, and DIP2C have a possible role in developmental dyslexia, intellectual disability, and developmental delay.26 Among ASD cases one inherited frameshift and two de novo mutations in the DIP2C gene have been reported.27, 28 Case G also carries two paternally inherited CNVs and a point mutation in COL4A2, but none in DIP2C (Figure 1).