Introduction
Autism is considered a neurodevelopmental problem. The disease comprises problems with language skills and social communication, and relevant repetitive behaviors. The total number of children in the United States affected by autism is 1 in 88 children, and the ratio of 4:1 males versus females exists.
There is a saying about autistic children that if you are able to know ONE child with autistic symptoms, you only know ONE child with autism. That is to say that each child with autistic symptoms is unique and rarely shows similarities in symptoms amongst them. However, where from do the symptoms of autism arise? Is it from the genes or the environment?
Over the last few decades, the etiology of autism has been an intriguing question, with the genetic predisposition hypothesis to autism, on one hand, prompting many scientists to look for an “autism gene.” On the other hand, research on the impact of adverse environmental factors and lack of maternal warmth as the predisposing reasons to autism was conducted. Let us delve into the research studies that support the nature or nurture debate for autism development.
Nature: Genetics as a Reason
It was found that genetics played a role in all forms of behaviors of human beings. This was not confined to schizophrenia or autism, but also extended to the attitudes and beliefs that an individual held. Also, the findings by point out that autism was, to a great degree, controlled by the genetic element, and multiple genetic loci have been implicated in playing a role in the development of the disorder. Powledge (2011) has shown that genomic imprinting has a role in autism development.
The concordance between monozygotic twins showed 60% whereas that between dizygotic twins was only 5% when it came to the genetic theory explaining autism. However, the monozygotic twins that were affected by the gene variant showed similar characteristics of the disease than did the dizygotic twins thus, pointing out to the importance of non-genetic factors playing a role in the disease development. In addition, one newly found class of genes responsible for autism was found to be controlled by neuronal activity thus, depicting that both environmental and genetic variations may contribute to autism development. Thus, many lately originated models show that both genetic and environmental factors are involved in the development of autism.
Nurture: Social Environment as a Reason
The liability to the development of autism may have a 90% level hereditability although environmental factors definitely have a role to play too (Currenti, 2010). There had been reports of children, with features of autism, who had been subjected to severe deprivation or trauma. Various studies on the Rhesus monkeys pointed out that the monkeys that had been maternally deprived showed characteristics of autism. In the year 1999, about 12 percent of Romanian children were reported to show quasi-autistic characteristics, who had been severely deprived as an orphan. At age 4, when these children had been adopted in the UK, they showed autism features no different from typically autistic children.
Additionally, visually impaired children were seen to also show symptoms of autism; the degree of the autism varied with the severity of mental retardation and blindness. These instances throw light on the fact that there may be correlations between autism, sensory deprivation, and congenital blindness. Further, Mohamed et al (2015) showed that exposure to toxic metals early on in life may lead to autism. About 25.71% of children who had vitamin D deficiency also showed symptoms of autism (Zaky et al., 2015).
Nature and Nurture –Conclusion
Scientists originally observed and recorded that autistic children had parents who showed similar characteristics, such as language deficits, behavioral problems, and face-processing deficits. Thus, the autistic features like face-processing deficits may be linked to similar deficits having developed in their offspring. However, there have also been observations that infants being “institutionalized” in the form of having no parental care for prolonged periods having autism show that environment plays a role in the condition’s development too.
The causes for autism when Mother Nature is involved includes (1) genetics, (2) immunology, and (3) parental age.
The causes for autism when Mother Nurture is involved includes (1) environmental, (2) drugs and (3) inflammation.
The manifestations of autistic symptoms are both biological and behavioral. The biological symptoms include slow development and growth, slow motor skills, abnormally sized brain, and seizures occurrence.
The behavioral symptoms include lack of interest in people, inability to identify facial expression, cues, and emotions; lack of ability to communicate, and repetitive motion of the body and not having the capacity to understand language.
References
Currenti, S. A., (2010) Understanding and determining the etiology of autism. Cell Mol. Neurobiol 30, 161-171.
Mohamed F. E., et al. (2015) Assessment of hair aluminum, lead, and mercury in a sample of autistic Egyptian children: environmental risk factors of heavy metals in autism. Behavioural Neurology, 1-9.
Powledge, T. M., (2011), Behavioral Epigenetics: How Nurture Shapes Nature, BioScience (2011) 61 (8): 588-592.doi: 10.1525/bio.2011.61.8.4
Zaky, E. A. et al., (2015) Prevalence of autism spectrum disorders in vitamin D deficient or insufficient rickets. International Journal of Science and Research 4 (6), 1365-1373.
