A 380-kb Duplication in 7p22.3 Encompassing the LFNG Gene in a Boy with Asperger Syndrome

The Notch signaling pathway inhibitor Dapt alleviates autism-like behavior, autophagy and dendritic spine density abnormalities in a valproic acid-induced animal model of autism

Autism spectrum disorders (ASDs) comprise a number of heterogeneous neurodevelopmental diseases. Recent studies suggest that the abnormal transmission of neural signaling pathways is associated with the pathogenesis of autism. The aim of this study was to identify a link between the Notch signaling pathway and the pathogenesis of autism. In this study, we demonstrated that prenatal exposure to valproic acid (VPA) resulted in autistic-like behaviors in offspring rats and that the expression of the Notch signaling pathway-related molecules Notch1, Jagged1, Notch intracellular domain (NICD) and Hes1 increased in the prefrontal cortex (PFC), hippocampus (HC) and cerebellum (CB) of VPA rats compared to those of controls. However, inhibiting the Notch pathway with (3,5-Difluorophenacetyl)-L-alanyl-S-phenylglycine-2-butyl Ester (Dapt) reduced the overexpression of Notch pathway-related molecules in offspring rats. Notably, Dapt improved autistic-like behaviors in a VPA-exposed rat model of autism. Furthermore, we investigated whether Dapt improved autistic-like behavior in a VPA rat model by regulating autophagy and affecting the morphology of dendritic spines. We found that the expression of the autophagy-related proteins Beclin 1, LC3B and phospho-p62 in the PFC, HC and CB of VPA model rats increased after Notch signal activation and was inhibited by Dapt compared to those of controls. Moreover, postsynaptic density-95 (PSD-95) protein expression also increased significantly compared to that of VPA model rats. The density of dendritic spines decreased in the PFC of VPA rats treated with Dapt compared to that of VPA model rats. Our present results suggest that VPA induces an abnormal activation of the Notch signaling pathway. The inhibition of excessive Notch signaling activation by Dapt can alleviate autistic-like behaviors in VPA rats. Our working model suggests that the Notch signaling pathway participates in the pathogenesis of autism by regulating autophagy and affecting dendritic spine growth. The results of this study may help to elucidate the mechanism underlying autism and provide a potential strategy for treating autism.

Screening for Subtelomeric Rearrangements in Thai Patients with Intellectual Disabilities Using FISH and Review of Literature on Subtelomeric FISH in 15,591 Cases with Intellectual Disabilities

We utilized fluorescence in situ hybridization (FISH) to screen for subtelomeric rearrangements in 82 Thai patients with unexplained intellectual disability (ID) and detected subtelomeric rearrangements in 5 patients. Here, we reported on a patient with der(20)t(X;20)(p22.3;q13.3) and a patient with der(3)t(X;3)(p22.3;p26.3). These rearrangements have never been described elsewhere. We also reported on a patient with der(10)t(7;10)(p22.3;q26.3), of which the same rearrangement had been reported in one literature. Well-recognized syndromes were detected in two separated patients, including 4p deletion syndrome and 1p36 deletion syndrome. All patients with subtelomeric rearrangements had both ID and multiple congenital anomalies (MCA) and/or dysmorphic features (DF), except the one with der(20)t(X;20), who had ID alone. By using FISH, the detection rate of subtelomeric rearrangements in patients with both ID and MCA/DF was 8.5%, compared to 2.9% of patients with only ID. Literature review found 28 studies on the detection of subtelomeric rearrangements by FISH in patients with ID. Combining data from these studies and our study, 15,591 patients were examined and 473 patients with subtelomeric rearrangements were determined. The frequency of subtelomeric rearrangements detected by FISH in patients with ID was 3%. Terminal deletions were found in 47.7%, while unbalanced derivative chromosomes were found in 47.9% of the rearrangements.

A Case of the 7p22.2 Microduplication: Refinement of the Critical Chromosome Region for 7p22 Duplication Syndrome

We report a 14-year-old Hispanic male with a microduplication of the chromosome 7p22.2 band detected through microarray analysis. He had a history of developmental delay and mild intellectual disability, asthma, myopia, proportionate short stature, dysmorphic features, and Achilles tendon release. This appears to be the first report of a patient with a microduplication of only the chromosome 7p22.2 band and is now the smallest reported duplication to date to include features in common with the chromosome 7p22 duplication syndrome.

3p22.1p21.31 microdeletion identifies CCK as Asperger syndrome candidate gene and shows the way for therapeutic strategies in chromosome imbalances

Background

In contrast to other autism spectrum disorders, chromosome abnormalities are rare in Asperger syndrome (AS) or high-functioning autism. Consequently, AS was occasionally subjected to classical positional cloning. Here, we report on a case of AS associated with a deletion of the short arm of chromosome 3. Further in silico analysis has identified a candidate gene for AS and has suggested a therapeutic strategy for manifestations of the chromosome rearrangement.

Results

Using array comparative genomic hybridization, an interstitial deletion of 3p22.1p21.31 (~2.5 Mb in size) in a child with Asperger’s syndrome, seborrheic dermatitis and chronic pancreatitis was detected. Original bioinformatic approach to the prioritization of candidate genes/processes identified CCK (cholecystokinin) as a candidate gene for AS. In addition to processes associated with deleted genes, bioinformatic analysis of CCK gene interactome indicated that zinc deficiency might be a pathogenic mechanism in this case. This suggestion was supported by plasma zinc concentration measurements. The increase of zinc intake produced a rise in zinc plasma concentration and the improvement in the patient’s condition.

Conclusions

Our study supported previous linkage findings and had suggested a new candidate gene in AS. Moreover, bioinformatic analysis identified the pathogenic mechanism, which was used to propose a therapeutic strategy for manifestations of the deletion. The relative success of this strategy allows speculating that therapeutic or dietary normalization of metabolic processes altered by a chromosome imbalance or genomic copy number variations may be a way for treating at least a small proportion of cases of these presumably incurable genetic conditions.