Uncovering the Secrets of Sperm Methylation in Adults at Risk of Autistic Offspring

At Risk of Autistic Offspring? Sperm DNA Methylation May Hold the Answer

Andrew Feinberg and team at the John Hopkins University Center for Epigenetics have found a DNA methylation pattern in the sperm of fathers with an increased risk of fathering autistic children that is also present in brains of unrelated autistic children. Image by .Eddy Adams

2015 Study Abstract

Epigenetic mechanisms such as altered DNA methylation have been suggested to play a role in autism, beginning with the classical association of Prader-Willi syndrome, an imprinting disorder, with autistic features.

Here we tested for the relationship of paternal sperm DNA methylation with autism risk in offspring, examining an enriched-risk cohort of fathers of autistic children.

We examined genome-wide DNA methylation (DNAm) in paternal semen biosamples obtained from an autism spectrum disorder (ASD) enriched-risk pregnancy cohort, the Early Autism Risk Longitudinal Investigation (EARLI) cohort, to estimate associations between sperm DNAm and prospective ASD development, using a 12-month ASD symptoms assessment, the Autism Observation Scale for Infants (AOSI). We analysed methylation data from 44 sperm samples run on the CHARM 3.0 array, which contains over 4 million probes (over 7 million CpG sites), including 30 samples also run on the Illumina Infinium HumanMethylation450 (450K) BeadChip platform (∼485 000 CpG sites). We also examined associated regions in an independent sample of post-mortem human brain ASD and control samples for which Illumina 450K DNA methylation data were available.

Using region-based statistical approaches, we identified 193 differentially methylated regions (DMRs) in paternal sperm with a family-wise empirical P-value [family-wise error rate (FWER)]

These data suggest that epigenetic differences in paternal sperm may contribute to autism risk in offspring, and provide evidence that directionally consistent, potentially related epigenetic mechanisms may be operating in the cerebellum of individuals with autism.

Sources and more information
  • Paternal sperm DNA methylation associated with early signs of autism risk in an autism-enriched cohort, Int. J. Epidemiol, doi: 10.1093/ije/dyv028, April 14, 2015.
  • At Risk of Autistic Offspring? Sperm DNA Methylation May Hold the Answer, epigenie, APRIL 23, 2015.

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