TP53 and Mobius syndrome: According to molecular characteristics, MB is classified into four groups: WNT (wingless-related integration site)-activated MBs, SHH (sonic hedgehog)-activated MBs which are separated into TP53-mutant and TP53-wild-types, and non-WNT/non-SHH MBs, comprising group 3 and group 4 which are listed as provisional variants [5].