Identification of SATB2 as the cleft palate gene on 2q32-q33.
Cell and Molecualr Genentics, MRC Human Genetics Unit, Western General Hospital, Edinburgh, EH4 2XU, UK. firstname.lastname@example.org
Cytogenetic evidence, in the form of deletions and balanced translocations, points to the existence of a locus on 2q32-q33, for which haploinsufficiency results in isolated cleft palate (CPO). Here we show by high-resolution FISH mapping of two de novo CPO-associated translocations involving 2q32-q33 that one breakpoint interrupts the transcription unit of the gene encoding the DNA-binding protein SATB2 (formerly KIAA1034). The breakpoint in the other translocation is located 130 kb 3' to the SATB2 polyadenylation signal, within a conserved region of non-coding DNA. The SATB2 gene is transcribed in a telomeric to centromeric direction and lies in a gene-poor region of 2q32-q33; the nearest confirmed gene is 1.26 Mb centromeric to the SATB2 polyadenylation signal. SATB2-encoding transcripts are assembled from 11 exons that span 191 kb of genomic DNA. They encode a protein of 733 amino acids that has two CUT domains and a homeodomain and shows a remarkable degree of evolutionary conservation, with only three amino acid substitutions between mouse and human. This protein belongs to the same family as SATB1, a nuclear matrix-attachment region binding protein implicated in transcriptional control and control of chromatin remodelling. There are also sequence similarities to the Drosophila protein DVE. Whole mount in situ hybridization to mouse embryos shows site- and stage-specific expression of SATB2 in the developing palate. Despite the strong evidence supporting an important role for SATB2 in palate development, mutation analysis of 70 unrelated patients with CPO did not reveal any coding region variants.
Human molecular genetics 2003;12;19;2491-501
The del(2)(q32.2q33) deletion syndrome defined by clinical and molecular characterization of four patients.
Center for Human Genetics, University of Leuven, Heresraat 49, 3000 Leuven, Belgium. Griet.VanBuggenhout@uz.kuleuven.ac.be
We report four patients with an interstitial deletion of chromosome 2q32-->2q33. They presented similar clinical findings including pre- and postnatal growth retardation, distinct facial dysmorphism, thin and sparse hair and fair built, micrognathia, cleft or high palate, relative macroglossia, dacrocystitis, persisting feeding difficulties, inguinal hernia and broad based gait. All were severely mentally retarded. Three patients had a specific behavioral phenotype with hyperactivity and motor restlessness, chaotic behavior, happy-personality but with periods of aggression and anxiety, sleeping problems and self-mutilation. (head-banging). Array CGH and fluorescence in situ hybridization (FISH) allowed us to delineate the deletion size and showed that the four patients share a 8.1 Mb minimal deleted region. Reviewing additional nine case reports of patients with similar deletions showed striking phenotypic similarities which enabled the delineation of the 2q32.2q33 syndrome. Deletion of 2q32 has been also associated with the wrinkly skin syndrome (WWS) and isolated cleft palate. Although the patients presented here shared many aspects of WWS, they did not had the wrinkly skin. All patients had a cleft or high palate, most likely as a result of hemizygosity for SATB2. A potential commonly deleted interval of the three patients with behavioral problems, excluding the deletion in the patient without behavioral problems, is at most 0.5 Mb in size harboring only two genes.
European journal of medical genetics 2005;48;3;276-89