Postzygotic and germinal de novo mutations in ASD: exploring their biological role

De novo mutations (DNMs), including germinal and postzygotic mutations (PZMs), are a strong source of causality for Autism Spectrum Disorder (ASD). However, the biological processes involved behind them remain unexplored. Our aim was to detect DNMs (germinal and PZMs) in a Spanish ASD cohort (360 trios) and to explore their role across different biological hierarchies (gene, biological pathway, cell and brain areas) using bioinformatic approaches. For the majority of the analysis, a combined cohort (N=2171 trios) with ASC (Autism Sequencing Consortium) previously published data was created. New plausible candidate genes for ASD such as FMR1 and NFIA were found. In addition, genes harboring PZMs were significantly enriched for miR-137 targets in comparison with germinal DNMs that were enriched in GO terms related to synaptic transmission. The expression pattern of genes with PZMs was restricted to early mid-fetal cortex. In contrast, the analysis of genes with germinal DNMs revealed a spatio-temporal window from early to mid-fetal development stages, with expression in the amygdala, cerebellum, cortex and striatum. These results provide evidence of the pathogenic role of PZMs and suggest the existence of distinct mechanisms between PZMs and germinal DNMs that are influencing ASD risk. ### Competing Interest Statement The authors have declared no competing interest. * AAF : alternate allele frequency ADI-R : Autism Diagnostic Interview-Revised ADOS : Autism Diagnostic Observation Schedule ASD : Autism Spectrum Disorder BEE : brain expressed enhancers BF : bayesian factor DNMs : de novo mutations EWCE : Expression Weighted Cell type Enrichment ExAC : Exome Aggregation Consortium FDR : false discovery rate FSHD : Facioscapulohumeral Muscular Dystrophy GO : gene ontology GQ : genotype quality ID : intellectual disability LoF : loss of function NDD : neurodevelopmental disorder OMIM : Online Mendelian Inheritance in Man pSI : specifity index statistic PZMs : postzygotic mutations TADA : transmission and de novo association test VCF : variant call format WES : whole exome sequencing