Factors Other Than Environment That May Be Contributing to ASD 161noncoding RNA (ncRNA), are currently considered to initiate and sustain
epigenetic change. New and ongoing research is constantly uncovering the
role of epigenetic changes in a variety of human disorders and fatal diseases.
Most epigenetic studies are of microRNAs (miRNAs) that are known to
control one‐third of human genes. These are small molecules that are known to
regulate a large part of life‐related functions and are involved in many disease
processes.
Currently, two epigenetic areas are most broadly studied – DNA methylation
and miRNAs. The latter is known to be involved in long term memory, chro-
matin remodeling, and histone modifications. The most interesting findings in
the epigenetic studies are about the relationship between epigenetic changes
and a host of disorders including various cancers, mental retardation associ-
ated disorders, immune disorders, and intellectual disorders.
Epigenetic Changes and the Environment: How Lifestyle
Can Influence Epigenetic Change from One Generation
to the Next
The growing understanding of interaction between the environment and
genetics may influence epigenetic changes or vice versa. These changes may be
reflected at various stages throughout a person’s life and even in later genera-
tions. For example, human epidemiological studies have provided evidence
that gestation in utero and early postnatal environmental factors influence the
adult risk of developing various chronic diseases and behavioral disorders.
Studies have shown that children born during the period of the Dutch famine
from 1944 to 1945 have increased rates of coronary heart disease and obesity
as a result of maternal exposure to famine during early pregnancy, compared
with those not exposed to famine. Similarly, adults who were prenatally
exposed to famine conditions have also been reported to have significantly
higher incidence of schizophrenia.
Factors Other Than Environment That May
Be Contributing to ASD
Older Age of Mother and Increased Risk
During the investigation on the birth of children born in California during the
1990s, it was concluded that the risks for having autistic children were signifi-
cantly higher for older women giving birth. It was concluded that it was 51%
more likely for women older than age 40 to give birth to an autistic child, than
mothers between the ages of 25 and 29 (Figure 6.6). Furthermore, it was also