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The Forkhead box G1 (FOXG1) gene has been implicated in severe Rett-like phenotypes. It encodes the Forkhead box protein G1, a winged-helix transcriptional repressor critical for forebrain development. Recently, the core FOXG1 syndrome was defined as postnatal microcephaly, severe mental retardation, absent language, dyskinesia, and dysgenesis of the corpus callosum. We present seven additional patients with a severe Rett-like neurodevelopment disorder associated with de novo FOXG1 point mutations (two cases) or 14q12 deletions (five cases). We expand the mutational spectrum in patients with FOXG1-related encephalopathies and precise the core FOXG1 syndrome phenotype. Dysgenesis of the corpus callosum and dyskinesia are not always present in FOXG1-mutated patients. We believe that the FOXG1 gene should be considered in severely mentally retarded patients (no speech-language) with severe acquired microcephaly (−4 to−6 SD) and few clinical features suggestive of Rett syndrome. Interestingly enough, three 14q12 deletions that do not include the FOXG1 gene are associated with phenotypes very reminiscent to that of FOXG1-mutation-positive patients. We physically mapped a putative long-range FOXG1-regulatory element in a 0.43 Mb DNA segment encompassing the PRKD1 locus. In fibroblast cells, a cis-acting regulatory sequence located more than 0.6 Mb away from FOXG1 acts as a silencer at the transcriptional level. These data are important for clinicians and for molecular biologists involved in the management of patients with severe encephalopathies compatible with a FOXG1-related phenotype. [ABSTRACT FROM AUTHOR]

Elevated transforming growth factor (TGF)-? signaling has been implicated in the pathogenesis of syndromic presentations of aortic aneurysm, including Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS). However, the location and character of many of the causal mutations in LDS intuitively imply diminished TGF-? signaling. Taken together, these data have engendered controversy regarding the specific role of TGF-? in disease pathogenesis. Shprintzen-Goldberg syndrome (SGS) has considerable phenotypic overlap with MFS and LDS, including aortic aneurysm. We identified causative variation in ten individuals with SGS in the proto-oncogene SKI, a known repressor of TGF-? activity. Cultured dermal fibroblasts from affected individuals showed enhanced activation of TGF-? signaling cascades and higher expression of TGF-?-responsive genes relative to control cells. Morpholino-induced silencing of SKI paralogs in zebrafish recapitulated abnormalities seen in humans with SGS. These data support the conclusions that increased TGF-? signaling is the mechanism underlying SGS and that high signaling contributes to multiple syndromic presentations of aortic aneurysm. [ABSTRACT FROM AUTHOR]

Myhre syndrome (MIM 139210) is a developmental disorder characterized by short stature, short hands and feet, facial dysmorphism, muscular hypertrophy, deafness and cognitive delay. Using exome sequencing of individuals with Myhre syndrome, we identified SMAD4 as a candidate gene that contributes to this syndrome on the basis of its pivotal role in the bone morphogenetic pathway (BMP) and transforming growth factor (TGF)-? signaling. We identified three distinct heterozygous missense SMAD4 mutations affecting the codon for Ile500 in 11 individuals with Myhre syndrome. All three mutations are located in the region of SMAD4 encoding the Mad homology 2 (MH2) domain near the site of monoubiquitination at Lys519, and we found a defect in SMAD4 ubiquitination in fibroblasts from affected individuals. We also observed decreased expression of downstream TGF-? target genes, supporting the idea of impaired TGF-?-mediated transcriptional control in individuals with Myhre syndrome. [ABSTRACT FROM AUTHOR]

NF1 microdeletion syndrome is a common dominant genomic disorder responsible for around 5% of type I neurofibromatosis cases. The majority of cases are caused by mutations arising within the NF1 gene. NF1 microdeletion carriers present a more severe phenotype than patients with intragenic mutations, including mental retardation, cardiac anomalies and dysmorphic features. Here, we report on two brothers with mental retardation presenting a microduplication of the NF1 microdeletion syndrome region detected by array-CGH analysis. Main phenotypic features are mental deficiency, early onset of baldness (15 years old), dental enamel hypoplasia and minor facial dysmorphism. The breakpoint regions coincide with the repeats, and the recombination hot spots shown to mediate NF1 microdeletion through NAHR. A screening of the patients' familial relatives showed that this microduplication segregates in the family for at least two generations. This result demonstrates that both deletion and duplication of the NF1 region, at cytogenetic band 17q11.2, give rise to viable gametes, even if only NF1 microdeletions have been reported until now. Our study reports seven cases of NF1 microduplication within one family. Similar phenotypic abnormalities were present in most of the individuals, however, two displayed a normal phenotype, suggesting a potential incomplete penetrance of the phenotype associated with NF1 microduplication.European Journal of Human Genetics (2008) 16, 305–311; doi:10.1038/sj.ejhg.5201978; published online 9 January 2008 [ABSTRACT FROM AUTHOR]