Genomic DNA Methylation Signatures Enable Concurrent Diagnosis and Clinical Genetic Variant Classification in Neurodevelopmental Syndromes

• Published in: American journal of human genetics Vol. 102; no. 1; pp. 156 - 174
• Main Authors: Aref-Eshghi, Erfan, Rodenhiser, David I., Schenkel, Laila C., Lin, Hanxin, Skinner, Cindy, Ainsworth, Peter, Paré, Guillaume, Hood, Rebecca L., Bulman, Dennis E., Kernohan, Kristin D., Boycott, Kym M., Campeau, Philippe M., Schwartz, Charles, Sadikovic, Bekim
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 04.01.2018; Elsevier
• Subjects: 5' Untranslated Regions - genetics; ATRX syndrome; Case-Control Studies; CHARGE syndrome; Child; Child, Preschool; Claes-Jensen syndrome; Cohort Studies; Demography; DNA Methylation - genetics; Epigenesis, Genetic; epigenomic machinery; Floating Harbor syndrome; Genome, Human; Humans; Kabuki syndrome; machine learning; Models, Genetic; molecular diagnosis; Mutation - genetics; Neurodevelopmental Disorders - blood; Neurodevelopmental Disorders - diagnosis; Neurodevelopmental Disorders - genetics; pediatric developmental disorders; Probability; Reproducibility of Results; Sotos syndrome; Young Adult; epigenomic machinery; Claes-Jensen syndrome; pediatric developmental disorders; Floating Harbor syndrome; Sotos syndrome; CHARGE syndrome; Kabuki syndrome; ATRX syndrome; machine learning; molecular diagnosis
• DOI: 10.1016/j.ajhg.2017.12.008
• ISSN: 0002-9297; 1537-6605

Pediatric developmental syndromes present with systemic, complex, and often overlapping clinical features that are not infrequently a consequence of Mendelian inheritance of mutations in genes involved in DNA methylation, establishment of histone modifications, and chromatin remodeling (the “epigenetic machinery”). The mechanistic cross-talk between histone modification and DNA methylation suggests that these syndromes might be expected to display specific DNA methylation signatures that are a reflection of those primary errors associated with chromatin dysregulation. Given the interrelated functions of these chromatin regulatory proteins, we sought to identify DNA methylation epi-signatures that could provide syndrome-specific biomarkers to complement standard clinical diagnostics. In the present study, we examined peripheral blood samples from a large cohort of individuals encompassing 14 Mendelian disorders displaying mutations in the genes encoding proteins of the epigenetic machinery. We demonstrated that specific but partially overlapping DNA methylation signatures are associated with many of these conditions. The degree of overlap among these epi-signatures is minimal, further suggesting that, consistent with the initial event, the downstream changes are unique to every syndrome. In addition, by combining these epi-signatures, we have demonstrated that a machine learning tool can be built to concurrently screen for multiple syndromes with high sensitivity and specificity, and we highlight the utility of this tool in solving ambiguous case subjects presenting with variants of unknown significance, along with its ability to generate accurate predictions for subjects presenting with the overlapping clinical and molecular features associated with the disruption of the epigenetic machinery.