The Relationship Between Ciliopathies and Autism
What are Ciliopathies
Ciliopathies are a relatively new classification of genetic diseases. According to an article published in the _Journal of Medical Genetics, “_Mutations in ciliary genes give rise to a multitude of human monogenic disorders that are now collectively known as ciliopathies.” In short, mutations in the cilia (small hair-like structures that protrude from cells and facilitate their movement) interfere with the normal operation of those cells, causing or contributing to a variety of genetic disorders and developmental abnormalities. Many of these genetic disorders were once thought unrelated, until the mutation of primary cilium was noted in each disease.
Ciliopathies and Autism
Disorders whose causes have been definitively linked to mutated cilia include Joubert, Meckel, and Bardet-Biedl Syndromes, as well as many others. However, other suspected ciliopathies include mental retardation, cognitive defects, and developmental delays. Such suspicions of genetic links to autism fuel much of today’s scientific research. Suspected genetic links propel scientists to further study the connection between ciliopathies and autism. Unfortunately, as many parents of children on the autism spectrum are painfully aware, the symptoms of autism overlap with other disorders, making concrete confirmation of diagnoses difficult, and study results suspect.
Ciliopathies such as Joubert and Bardet-Biedl Syndromes (BBS) share many similar symptoms as autism such as speech delays or impaired balance and coordination. In the case of BBS, problems with social skills and delayed social development are a primary symptom. In many cases, these genetic disorders mimic Autism spectrum disorders at initial onset. As a result, children with these disorders may first carry a misdiagnosis of autism spectrum disorder. Misdiagnosis, overlapping symptoms, and small group samplings make determining exact connections between cell mutations like ciliopathies and other genetic components with autism difficult. However, discussions of such connections abound.
No Concrete Evidence, Yet
Currently, there is little concrete evidence that directly links autism spectrum disorders with mutations in cilia or known ciliopathies. Research to confirm or deny genetic components and links to autism are the primary focus of numerous research projects. Such projects include mapping the specific genes or cell mutations that cause autism, including ciliopathies. For example, the Autism Genome Project, seeks to find and identify the genetic components that cause or contribute to autism. Perhaps, as this research develops, there may yet prove to be a link between ciliopathies and autism.
Mapping of autism genomes and genetic research with regard to cilium mutation is still in its infancy. In fact, until the last decade or so, cilia were thought to be merely a vestige of human evolution with no valid purpose. In her published report, The Importance of Being Cilia, Mary Beth Gardiner stated “…the primary cilium was long considered—with a few exceptions—to be a largely useless evolutionary vestige…now we know that cilia are functioning organelles, essential to normal development and health.”
With such developments in research and a better understanding of the genetics behind autism spectrum disorders, there is hope for better treatment options and preventative measures.
Autism Genome Project: https://www.autismgenome.org/research/geneticdisorders.htm
Howard Hughes Medical Institute, The Importance of Being Cilia: https://www.hhmi.org/bulletin/sept2005/features/cilia.html
Journal of Medical Genetics, Recent Advances…of Ciliopathies: https://jmg.bmj.com/content/45/5/257.full?rss=1