Copy Number Variation in Subjects with Major Depressive Disorder Who Attempted Suicide
PLOS ONE
Authors: Perlis, Roy H.; Ruderfer, Douglas; Hamilton, Steven P.; Ernst, Carl
Abstract
Background: Suicide is one of the top ten leading causes of death in North America and represents a major public health burden, partcularly for people with Major Depressive disorder (MD). Many studies have suggested that suicidal behavior runs in families, however, identification of genomic loci that drive this efffect remain to be identified. Methodology/Principal Findings: Using subjects collected as part of STAR*D, we genotyped 189 subjects with MD with history of a suicide attempt and 1073 subjects with Major Depressive disorder that had never attempted suicide. Copy Number Variants (CNVs) were called in Birdsuite and analyzed in PLINK. We found a set of CNVs present in the suicide attempter group that were not present in in the non-attempter group including in SNTG2 and MACROD2 - two brain expressed genes previously linked to psychopathology; however, these results failed to reach genome-wide signifigance. Conclusions: These data suggest potential CNVs to be investigated further in relation to suicide attempts in MD using large sample sizes.
Monozygotic twins discordant for submicroscopic chromosomal anomalies in 2p25.3 region detected by array CGH
CLINICAL GENETICS
Authors: Rio, M.; Royer, G.; Gobin, S.; Blois, M. C.; Ozilou, C.; Bernheim, A.; Nizon, M.; Munnich, A.; Bonnefont, J-P; Romana, S.; Vekemans, M.; Turleau, C.; Malan, V.
Abstract
Although discordant phenotypes in monozygotic twins with developmental disorder are not an exception, underlying genetic discordance is rarely reported. Here, we report on the clinical and cytogenetic details of 4-year-old female monozygotic twins with discordant phenotypes. Twin 1 exhibited global developmental delay, overweight and hyperactivity. Twin 2 had an autistic spectrum disorder. Molecular karyotyping in twin 1 identified a 2p25.3 deletion, further confirmed by Fluorescence in situ hybridization (FISH) analysis on leukocytes. Interestingly, array comparative genomic hybridization was normal in twin 2 but FISH analysis using the same probe as twin 1 showed mosaicism with one-third of cells with a 2p25.3 deletion, one-third of cells with a 2p25.3 duplication, and one-third of normal cells. Genotyping with microsatellite markers confirmed the monozygosity of the twins. We propose that the chromosome imbalance may be due to a mitotic non-allelic recombination occurring during blastomeric divisions of a normal zygote. Such event will result in three distinct cell populations, whose proportion in each embryo formed after separation from the zygote may differ, leading to discordant chromosomal anomalies between twins. We also discuss that the MYTL1L and the SNTG2 genes within the reported region could probably relate to the phenotypic discordance of the monozygotic twins.