MID1 and Opitz G/BBB syndrome: CUL4B mutation may result in X-linked mental retardation (Zou et al., 2007); whereas TRIM family of E3 ubiquitin ligases have been implicated in several developmental disorders, e.g., TRIM50 in Williams–Beuren syndrome (Micale et al., 2008), Midline 1 (MID1) in Opitz syndrome (Quaderi et al., 1997), and TRIM37 in Mulibrey Nanism (Kallijarvi et al., 2002).