Distinct Epileptogenic Mechanisms Associated with Seizures in Wolf-Hirschhorn Syndrome.

Seizures are one of the clinical hallmarks of Wolf-Hirschhorn syndrome (WHS), causing a significant impact on the life quality, still in the first years of life. Even that the knowledge about WHS-related seizure candidate genes has grown, cumulative evidence suggests synergic haploinsufficiency of distinct genes within cellular networks that should be better elucidated. Herein, we evaluated common mechanisms between candidate genes from WHS seizure-susceptibility regions (SSR) and genes globally associated with epilepsy. For this purpose, data from 94 WHS patients delineated by chromosomal microarray analysis were integrated into a tissue-specific gene network with gene expression, drugs, and biological processes. We found functional modules and signaling pathways involving candidate and new genes with potential involvement in the WHS-related seizure phenotype. The proximity among the previous reported haploinsufficient candidate genes (PIGG, CPLX1, CTBP1, LETM1) and disease genes associated with epilepsy suggests not just one, but different impaired mechanisms in cellular networks responsible for the balance of neuronal activity in WHS patients, from which neuron communication is the most impaired in WHS-related seizures. Furthermore, CTBP1 obtained the largest number of drug associations, reinforcing its importance for adaptations of brain circuits and its putative use as a pharmacological target for treating seizures/epilepsy in patients with WHS.

Shared Neurodevelopmental Perturbations Can Lead to Intellectual Disability in Individuals with Distinct Rare Chromosome Duplications.

Chromosomal duplications are associated with a large group of human diseases that arise mainly from dosage imbalance of genes within the rearrangements. Phenotypes range widely but are often associated with global development delay, intellectual disability, autism spectrum disorders, and multiple congenital abnormalities. How different contiguous genes from a duplicated genomic region interact and dynamically affect the expression of each other remains unclear in most cases. Here, we report a genomic comparative delineation of genes located in duplicated chromosomal regions 8q24.13q24.3, 18p11.32p11.21, and Xq22.3q27.2 in three patients followed up at our genetics service who has the intellectual disability (ID) as a common phenotype. We integrated several genomic data levels by identification of gene content within the duplications, protein-protein interactions, and functional analysis on specific tissues. We found functional relationships among genes from three different duplicated chromosomal regions, reflecting interactions of protein-coding genes and their involvement in common cellular subnetworks. Furthermore, the sharing of common significant biological processes associated with ID has been demonstrated between proteins from the different chromosomal regions. Finally, we elaborated a shared model of pathways directly or indirectly related to the central nervous system (CNS), which could perturb cognitive function and lead to ID in the three duplication conditions.