This research review is a very good summary of many of the genetic disorders that have ASD manifestations. It aims to look at the importance of X-linked genes to depict the importance of genetic linkage and causation of a spectrum of physiological and psychological behaviors and phenotypes.
The X-linked disorders with autism features described are those such as Turner syndrome (XO), Klinefelter syndrome (XXY), and fragile X syndrome etc. It uses examples such as these to really emphasize the important role of X-linked genes and their role in development.
This research article is successful in truly helping others understand the multiplexity of ASD, as well as the different outcomes. The underpinning molecular mechanism that leads to such a broad range of symptoms and behaviors, is more complex, and our current knowledge, is just the tip of the iceberg. More importantly, this article raises the concern of having broad terminology to address those with distinct and unique mutations and molecular pathways. It also addresses the challenges that researchers face when trying to understand the molecular basis of X-linked genes because of epigenetic factors, pleiotropic effects, imprinting, and X-inactivation. These variations lead to a range in severity of the disorder. Its a much more complex question than anyone can imagine.
Research in ASD is not sufficient to understand the fundamental biology of impaired language, impoverished social interaction, and repetitive activities and behavior. It is a complex system and requires the efforts from various sources and researchers to better understand the neurological circuits and molecular biology of the human species.
One critique about this research review is that it focuses on the named genetic disorders with ASD features, and it raised a lot of questions and concerns about the complexity and shortcomings we face in studying the genetic basis. However, we do have to note that this is an article published in 2006. The reason why we chose this review was because of its comprehensive analysis of various X-linked diseases and a good overview of why the X-chromosome is so important -- thus explaining the high susceptibility of ASD in males.
But what is more hopeful for the future, is that we now have new technologies such as CRISPR-gene editing and powerful bioinformatics tools to study molecular genetics in a much more comprehensive and systemic way. Meta-analysis of the whole genome, even specific mutations in specific locations in a gene are common practices in present-day research, and this will only expedite our progress in eventually understanding the genome and the molecular answer of the importance of the X-linked chromosome.
Whether there is a cure or not, is another question that science has to acknowledge and ethical implications of research findings are warranted to be weighted. But first, we have to understand the biology.