DNA methylation epi-signature and biological age in attention deficit hyperactivity disorder patients

OBJECTIVE

Attention Deficit/Hyperactivity Disorder (ADHD) is a common behavioral syndrome that begins in childhood and affects 3.4% of children worldwide. Due to its etiological complexity, there are no consistent biomarkers for ADHD, however the high heritability presented by the disorder indicates a genetic/epigenetic influence. The main epigenetic mechanism is DNA methylation, a process with an important role in gene expression and in many psychiatric disorders. Thus, our study sought to identify epi-signatures biomarkers in 29 children clinically diagnosed with ADHD.

METHODS

After DNA extraction and bisulfite conversion, we performed methylation array experiment for differential methylation, ontological and biological age analysis.

RESULTS

The biological response in ADHD patients was not sufficient to determine a conclusive epi-signature in our study. However, our results highlighted the interaction of energy metabolism and oxidative stress pathways in ADHD patients detected by differential methylation patterns. Furthermore, we were able to identify a marginal association between the DNAmAge and ADHD.

CONCLUSION

Our study present new methylation biomarkers findings associated with energy metabolism and oxidative stress pathways, in addition to DNAmAge in ADHD patients. However, we propose that further multiethnic studies, with larger cohorts and including maternal conditions, are necessary to demonstrate a definitive association between ADHD and these methylation biomarkers.

Rare genomic rearrangement in a boy with Williams-Beuren syndrome associated to XYY syndrome and intriguing behavior

Williams-Beuren syndrome (WBS) is caused by a hemizygous contiguous gene microdeletion of 1.55-1.84 Mb at 7q11.23 region. Approximately, 28 genes have been shown to contribute to classical phenotype of SWB with presence of dysmorphic facial features, supravalvular aortic stenosis (SVAS), intellectual disability, and overfriendliness. With the use of Microarray-based comparative genomic hybridization and other molecular cytogenetic techniques, is possible define with more accuracy partial or atypical deletion and refine the genotype-phenotype correlation. Here, we report on a rare genomic structural rearrangement in a boy with atypical deletion in 7q11.23 and XYY syndrome with characteristic clinical signs, but not sufficient for the diagnosis of WBS. Cytogenetic analysis of G-banding showed a karyotype 47,XYY. Analysis of DNA with the technique of MLPA (Multiplex Ligation-dependent Probe Amplification) using kits a combination of kits (P064, P036, P070, and P029) identified an atypical deletion on 7q11.23. In addition, high resolution SNP Oligonucleotide Microarray Analysis (SNP-array) confirmed the alterations found by MLPA and revealed others pathogenic CNVs, in the chromosomes 7 and X. The present report demonstrates an association not yet described in literature, between Williams-Beuren syndrome and 47,XYY. The identification of atypical deletion in 7q11.23 concomitant to additional pathogenic CNVs in others genomic regions allows a better comprehension of clinical consequences of atypical genomic rearrangements.