The CUL4B gene encodes a member of Cullin–RING ubiquitin ligase complex. Point mutations in CUL4B were identified recently in patients with syndromic X-linked mental retardation (XLMR). Here, using oligoarray-based comparative genomic hybridization (array CGH), we identified a de novo deletion of the CUL4B gene in a boy with syndromic mental retardation, minor facial anomalies, short stature, delayed puberty, hypogonadism, relative macrocephaly, gait ataxia, and pes cavus, all manifestations described previously in patients with CUL4B point mutations. Interestingly, our patient also presented with aortic valvular “dysplasia” and vertebral anomalies similar to those seen in Scheuermann disease, both of which may also be part of this syndrome. This report further suggests that point mutations and deletions of the CUL4B gene lead to a recognizable phenotype. The association of facial anomalies, short stature, hypogonadism, and gait ataxia in a mentally retarded boy should prompt molecular analyses of the CUL4B gene. © 2009 Wiley-Liss, Inc.