Even though autism undoubtedly has biological underpinnings and the brains of those with autism may share some form of common structures (neuroanatomy) or function (neurophysiology), we still don't have a good working definition for it - or at least, nothing that everyone can agree upon. In the field of cancer research, even though scientists disagree about the primary causes of a tumour developing, they can all generally agree that uncontrolled cellular growth is a good working definition. If you see a tumour, you know it's following some sort of poorly-regulated growth process, even when it's benign (non-cancerous). Which makes finding causes of tumour promotion considerably easier. If you know the end result in terms of cell biology, that limits the number of variables you're searching for as instigators of that process.
But not so for autism. Even though the well-known psychiatrist, Leo Kanner, described the condition well over 70 years ago, the only thing people can seem to agree upon is a behavioural definition. (And even still, we argue over that!) We have done so much research and have published so many papers reporting correlations with things that may influence the occurrence of autism, ranging from the presence of one or more other disorders or diseases, down to associated genes. But unlike cancer, we have no general definition for what defines autism at the level of the cell nor at the level of the brain. We're still wandering around our research somewhat blindly.
Ultimately, that means we study just about everything that appears to have an association with the condition without much understanding of whether the relationship is causal or simply correlational in nature. An excellent example of this comes from studying autism genetics. Over 3,000 genes have found to have minor-to-strong association with the condition, both those which currently have no known cause (idiopathic) and conditions which are characterized by the association of several clinically recognizable features which tend to go together (syndromic), such as Fragile X Syndrome. While all roads may have once led to Rome, not all genes lead to autism. Those thousands of genes represent at least 12% of the genes within the human genome, a staggering proportion. It's highly unlikely that all or most converge onto a single behavioural trait.
 |
| How people see autism. Image credit: Hepingting |
Ultimately, that means we study just about everything that appears to have an association with the condition without much understanding of whether the relationship is causal or simply correlational in nature. An excellent example of this comes from studying autism genetics. Over 3,000 genes have found to have minor-to-strong association with the condition, both those which currently have no known cause (idiopathic) and conditions which are characterized by the association of several clinically recognizable features which tend to go together (syndromic), such as Fragile X Syndrome. While all roads may have once led to Rome, not all genes lead to autism. Those thousands of genes represent at least 12% of the genes within the human genome, a staggering proportion. It's highly unlikely that all or most converge onto a single behavioural trait.
