Somatic mosaicism in the diseased brain.

It is hard to believe that all the cells of a human brain share identical genomes. Indeed, single cell genetic studies have demonstrated intercellular genomic variability in the normal and diseased brain. Moreover, there is a growing amount of evidence on the contribution of somatic mosaicism (the presence of genetically different cell populations in the same individual/tissue) to the etiology of brain diseases.

The Cytogenomic "Theory of Everything": Chromohelkosis May Underlie Chromosomal Instability and Mosaicism in Disease and Aging.

Mechanisms for somatic chromosomal mosaicism (SCM) and chromosomal instability (CIN) are not completely understood. During molecular karyotyping and bioinformatic analyses of children with neurodevelopmental disorders and congenital malformations ( = 612), we observed colocalization of regular chromosomal imbalances or copy number variations (CNV) with mosaic ones ( = 47 or 7.7%).

An interstitial deletion at 10q26.2q26.3.

We present a case of an interstitial subtelomeric 10q26 deletion in a male child with moderate developmental delay and minor dysmorphic features. Using array comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH), we have detected an interstitial deletion at 10q26.2q26.

Xq28 (MECP2) microdeletions are common in mutation-negative females with Rett syndrome and cause mild subtypes of the disease.

Background: Rett syndrome (RTT) is an X-linked neurodevelopmental disease affecting predominantly females caused by MECP2 mutations. Although RTT is classically considered a monogenic disease, a stable proportion of patients, who do not exhibit MECP2 sequence variations, does exist. Here, we have attempted at uncovering genetic causes underlying the disorder in mutation-negative cases by whole genome analysis using array comparative genomic hybridization (CGH) and a bioinformatic approach.

An interstitial 20q11.21 microdeletion causing mild intellectual disability and facial dysmorphisms.

We report a case of an interstitial chromosome 20q11.21 microdeletion in a 7-year-old male child presenting with mild intellectual disability and facial dysmorphisms. Array comparative genomic hybridization (CGH) has shown that the deletion resulted in the loss of 68 genes, among which 5 genes (COX4I2, MYLK2, ASXL1, DNMT3B, and SNTA1) are disease causing.

Molecular karyotyping by array CGH in a Russian cohort of children with intellectual disability, autism, epilepsy and congenital anomalies.

Background: Array comparative genomic hybridization (CGH) has been repeatedly shown to be a successful tool for the identification of genomic variations in a clinical population. During the last decade, the implementation of array CGH has resulted in the identification of new causative submicroscopic chromosome imbalances and copy number variations (CNVs) in neuropsychiatric (neurobehavioral) diseases. Currently, array-CGH-based technologies have become an integral part of molecular diagnosis and research in individuals with neuropsychiatric disorders and children with intellectual disability (mental retardation) and congenital anomalies.