SON and ZTTK syndrome: However, we also highlight many recoding sites with undefined roles in neuronal development: p.R61G site in cyclin I (CCNI), peaking postnatally in the cortex but not in the cerebellum; p.K95R site in insulin-like growth factor binding protein 7 (IGFBP7), peaking postnatally in the cerebellum but prenatally in the cortex; p.I64M and p.S75G sites in signal recognition particle 9 (SRP9) peaking postnatally across all regions; a postnatal biased p.R580G site in SON DNA and RNA binding protein (RBP) (SON, the cause of ZTTK syndrome), among others (Figures 4A and 4B).