Epigenetic modifications may play a role in the developmental consequences of early life events

Abstract

Many aspects of postnatal development are influenced by events before birth, including cognitive and language development. An adverse intrauterine environment, for example secondary to poor maternal nutritional status, multiple pregnancy, or late preterm birth, is associated with increased risks of delayed or impaired childhood development and altered physiology in adulthood that may predispose to increased risk of adult disease. Maternal periconceptional undernutrition and twin conception can both result in late preterm birth, but it is less clear whether cases of late preterm birth not following a recognized early pregnancy event may still have their origin in the periconceptional period. Thus, the very earliest periods of pregnancy, and perhaps even the pre-pregnancy period, may be an important period determining the developmental trajectory of the fetus, and thus both pregnancy and later health outcomes. Profound epigenetic modifications to the genome occur in the early embryo as a normal part of development. Recent evidence suggests that environmental signals acting during early development may also result in epigenetic changes which may play a role in mediating the association between early life exposures and later phenotype.

Toward epigenetic and gene regulation models of specific language impairment: looking for links among growth, genes, and impairments

“…A shared family history of LLE may reflect either genetic or environmental influences. The suboptimal fetal growth is consistent with possible epigenetic influences on birth weight [2]. An earlier case control study of 5-year-old children with SLI and controls [14] reported an association of parental learning histories but no statistically significant perinatal events, including birth weight, or maternal exposures to disease.…”

“…Genetic inquiry could help resolve some of the interpretive questions. There is increasing technical documentation of the powerful ways in which genes and gene expression influence development, at the cellular level and also at the cortical level, and how genes and gene expression influence the emergence (and decline) of general cognitive abilities in animal models as well as for human development [2-5,36,37]. Although the biological mechanisms are yielding to experimental methods, there is a large gap in the empirical human evidence base, particularly at the level of detailed longitudinal description of children’s language acquisition over the years encompassing the transition from child language to adult language.…”

“…This level of genetics inquiry would be a new direction that could build on and clarify the recent candidate gene discoveries reported for language, speech, and reading impairments, or shift attention to new mechanisms of gene regulation. The collection of papers in the special issue covered the following: the role of epigenetic modifications underlying the developmental consequences of early life events [2], recent candidate gene investigations, possible phenotypic interrelationships, and challenges for interpretation [3-5], a call for phenotypes at the level of neuronal pathways and local brain circuits involved in speech and language processing for the next generation of genetics/epigenetics investigation [6], and how the effects of cochlear implants on deaf children’s language acquisition depend on the age of implant, suggesting possible epigenetic influences [7]. …”

Journal of Neurodevelopmental Disorders is now a fully open access journal

“…The most recent issue (vol 3, issue 4) [2] included papers on Turner Syndrome, Autism Spectrum Disorder, Prader-Willi Syndrome, William's Syndrome, Fragile X, Specific Language Impairment and Stuttering, and covered a wide-range of cross-cutting perspectives from the effects of prenatal exposures on risk for autism to the impact of sex differences on the developing brain. In this same issue, the Special Section entitled 'Building an Epigenetics Perspective on Language, Speech and Reading Impairments', edited by Mabel Rice [3], examined in more detail genetic mechanisms underlying disorders of communication. Clearly this new Journal has met the challenge of integrating across multiple perspectives and over multiple levels of analysis.…”

Exposure to childhood traumas ups the odds of giving birth to daughters

“…Among the most likely are atypical levels of corticotropin releasing hormone (CRH) and cortisol that are associated with PTSD and which have been shown to impact important aspects of reproduction, including the timing of delivery and weight of infants at birth (Morland et al 2007; Seng et al 2011; Wadhwa 2005). In addition, PTSD could affect women’s antenatal health via immune dysfunction (review in Pace and Heim, 2011), altered gene expression (Bloomfield 2011), and maladaptive health behaviors (Owen et al 2005; Seng et al 2008; Yampolsky et al 2010) - any one of which could ultimately lead to a disproportional loss of weaker embryos/fetuses, which are more likely male (Elsmén et al 2004). Other possibilities include stress-related increases in androgens during pregnancy, which could affect fetal development especially among males (James, 2012).…”