SMO and Mobius syndrome: Advancements in cancer genomics and genome-wide transcription profiling now show that MBs comprise at least four molecular subgroups, termed Wingless (WNT-MB: mutations in CTNNB1, DDX3X, Chromatin-remodeling genes, and TP53), Sonic Hedgehog (SHH-MB: mutations in PTCH1, SMO, SUFU, TERT promoter, and Chromatin-remodeling genes), Group 3 (G3: mutations in SMARCA4, chromatin-remodeling genes, and genes of the TGF-β pathway), and Group 4 (G4: chromatin-remodeling genes) (12).