A fascinating project conducted be a team of US molecular geneticists based at Mount Sinai and led by professor Joseph Buxbaum have been mapping the genome of autistic people.
The researched involved 810 volunteers – 60% of which had been formally diagnosed with ASD, with the remaining 40% neurotypical.
The research showed that the autistic group tended to have a very specific group of missing genes.
A simple, but important fact about genetics, is that genes can be switched on and off, but they can also be deleted. This isn’t an uncommon occurence, in fact everyone has certain genes which are deleted, that is the reason we all look different, or may look more like one parent, rather than another. Even twins can have deleted genes, leading to one twin being genetically predisposed to an illness or genetic condition that the other is not.
The genes that were noticeably absent in the autistic group were among many genes that control a biological system called Autophagy; a complicated system which deals with programmed cell death and cell replacement and repair.
It has long been thought that Autophagy is important in brain development. During the early years of our development an almost countless number of synapses are formed, allowing the developing brain to learn, experiment and improve. All of these connections are created and controlled through the process of Autophagy – and as many of these connections prove to be useless, they are destroyed by the same process. Professor Buxbaum’s team suggest that these deleted genes lead to a system were perhaps not enough of these connections are removed, leading to a brain which is essentially “mis-wired”.
Genetics is a very complicated science and has been proven much more so in the last 20 years. While Professor Buxbaum’s research is not conclusive, it does seem to be following the pattern that there may not be a single defining cause of Autistic Spectrum Disorders, but rather a much more subtle system at play, were genetics, our environment, and even the environment of our ancestors can have a profound affect on whether autism occurs in a child or not.