From genetics to epigenetics: new perpectives in Tourette Syndrome research

Gilles de la Tourette Syndrome (TS) is a neurodevelopmental disorder marked by the appearance of multiple involuntary motor and vocal tics. TS presents high comorbidity rates with other disorders such as attention deficit hyperactivity disorder (ADHD) and obsessive compulsive disorder (OCD). TS is highly heritable and has a complex polygenic background. However, environmental factors also play a role in the manifestation of symptoms. Different epigenetic mechanisms may represent the link between these two causalities. Epigenetic regulation has been shown to have an impact in the development of many neuropsychiatric disorders, however very little is known about its effects on Tourette Syndrome.This review provides a summary of the recent findings in the genetic background of TS, followed by an overview on different epigenetic mechanisms, such as DNA methylation, histone modifications and non-coding RNAs in the regulation of gene expression. Epigenetic studies in other neurological and psychiatric disorders are discussed along with the TS-related epigenetic findings available in the literature to date. Moreover, we are proposing that some general epigenetic mechanisms seen in other neuropsychiatric disorders may also play a role in the pathogenesis of TS

Search for copy number variants in chromosomes 15q11-q13 and 22q11.2 in obsessive compulsive disorder

<p>Abstract</p> <p>Background</p> <p>Obsessive-compulsive disorder (OCD) is a clinically and etiologically heterogeneous syndrome. The high frequency of obsessive-compulsive symptoms reported in subjects with the 22q11.2 deletion syndrome (DiGeorge/velocardiofacial syndrome) or Prader-Willi syndrome (15q11-13 deletion of the paternally derived chromosome), suggests that gene dosage effects in these chromosomal regions could increase risk for OCD. Therefore, the aim of this study was to search for microrearrangements in these two regions in OCD patients.</p> <p>Methods</p> <p>We screened the 15q11-13 and 22q11.2 chromosomal regions for genomic imbalances in 236 patients with OCD using multiplex ligation-dependent probe amplification (MLPA).</p> <p>Results</p> <p>No deletions or duplications involving 15q11-13 or 22q11.2 were identified in our patients.</p> <p>Conclusions</p> <p>Our results suggest that deletions/duplications of chromosomes 15q11-13 and 22q11.2 are rare in OCD. Despite the negative findings in these two regions, the search for copy number variants in OCD using genome-wide array-based methods is a highly promising approach to identify genes of etiologic importance in the development of OCD.</p

Expresison of Fc(γ)RII and CD4 receptors by normal human megakaryocytes

We studied human megakaryocytes to determine if they both expressed and synthesized Fc(γ) and CD4 membrane receptors. The strategy employed relied on demonstration of receptor protein and mRNA in megakaryocytes present in freshly made marrow smears, or in megakaryocytes isolated from aspirated normal bone marrow by counterflow centrifugal elutriation. Protein was detected immunochemically, whereas mRNA was detected either by in situ hybridization, or by reverse transcription, polymerase chain reaction (RT-PCR). Using these methods CD4 and Fc(γ)RII protein and mRNA were detected in most megakaryocytes. Fc(γ)RI and Fc(γ)RIII protein was not detected in these cells. Megakaryocytes were also cultured with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) to determine the effect of this growth factor on Fc(γ)RII expression. As has been noted in cells of the monocyte-macrophage lineage, exposure to rhGM-CSF resulted in a significant increase in the level of megakaryocyte Fc(γ)RII mRNA and protein. These observations are significant because they provide a physiologic basis for known viral trophism displayed by megakaryocytes. They are also of interest because they suggest that alternative portals exist for entry of human immunodeficiency virus (HIV-1) into megakaryocytes and that such infection may play a role in acquired immunodeficiency syndrome (AIDS)-related thrombocytopenia