These new cases give additional support to the genetic heterogeneity in RTT and help to delineate the clinical spectrum of the FOXG1-related phenotypes. FOXG1 screening should be considered in the molecular diagnosis of RTT.

No abstract

Mutations in the X-linked methyl-CpG-binding protein 2 gene (MECP2) have been found to be a cause of Rett syndrome (RTT). In order to provide further insights into the distribution and the spectrum of mutations, we investigated, in addition to the whole coding sequence, a phylogenetically conserved sequence within the 3' untranslated region (3' UTR) of the MECP2 gene for 55 sporadic RTT, including 47 typical and 8 nonclassical cases. We have developed an approach based on conformation-sensitive gel electrophoresis, sequence analysis and, for the first time, Southern blot analysis. Mutation detection, including unreported gross DNA rearrangements, was achieved in 79% of classical RTT and 25% of nonclassical RTT patients. The high prevalence of recurrent mutations allows us to propose a molecular diagnosis strategy for RTT.

Exposure to HPV vaccines was not associated with an increased risk of ADs within the time period studied. Results were robust to case definitions and time windows of exposure. Continued active surveillance is needed to confirm this finding for individual ADs.

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 ( À4 to À6 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.