Epigenomic correlates of co-morbid psychosis in 22q deletion syndrome.
Abstract
Purpose
22q11.2 deletion syndrome (22q11DS) confers one of the strongest genetic risks of psychiatric disorders, with up to 25% of 22q11DS patients developing symptoms of psychosis. The broad phenotypic spectrum, variable deletion size, and lack of a defined pathogenic mechanism make it likely that 22q11DS phenotypes are mediated by non-genetic factors, such as epigenetics.
Methods
We developed a DNA methylation (DNAm) signature for 22q11DS in whole blood from 41 individuals with the common 2.54Mb 22q11.2 deletion and 42 matched controls using the Illumina MethylationEPIC v.2.0 array. We used the signature to classify a cohort with 22q11DS (n=108), stratified by deletion size, or with the reciprocal duplication syndrome (n=18), and ran a secondary genome-wide analysis on psychotic disorders in 22q11DS.
Results
Our 22q11DS DNAm signature demonstrated 100% specificity (n=259/259) and 96% sensitivity (n=49/51), independent of deletion size. Individuals with 22q11.2 duplication syndrome did not carry identifiable DNAm alterations, despite phenotypic overlap with 22q11DS. Within the 22q11DS cohort, we found 16 differentially methylated regions between individuals with and without a psychosis spectrum disorder.
Conclusion
DNAm continues to provide new insights into 22q11DS, including psychosis risk and, in the future, may serve as a reliable predictor of co-morbidities within this broad phenotype.