According to a new study, about 90% of autism spectrum disorders are related to hereditary factors.
Don't store avocado like this: it's dangerousAutism? It depends on the genes have been identified.. About 90% of autism spectrum disorders, in fact, would depend on hereditary factors, while only a small part can be attributed to external factors, such as exposure to pollutants when one is still in the mother's womb.
This is demonstrated by a study carried out by Sven Sandin of the Icahn School of Medicine at Mount Sinai in New York, published in the scientific journal JAMA, which puts hereditary factors as the main culprits of autism in the dock.
The survey examined 37.570 pairs of twins, 2.642.064 pairs of non-twin siblings, 432.281 pairs of siblings with the same mother and different father, 445.531 siblings with the same father but different mother and 14.516 diagnoses of autism in the entire sample.
By comparing twins and non-twins, it is possible to estimate the weight of genes and the environmental factor on the presence or absence of certain diseases, because while identical twins (homozygotes) have identical DNA, so much so that all the differences between them depend on non-environmental factors. shared by both, the siblings have the same DNA for 50% and the stepbrothers, on the other hand, for 25%. The study found that two siblings' risk of being both autistic increases as their genetic similarity increases: this means that the heritability of autism is quite high (83%), while external environmental factors matter much less (17%).
The risk of two siblings of both being autistic is therefore lowest among half siblings (those who have only one parent in common), higher among siblings and highest among twins.
It is therefore evident, the researchers conclude, that the genetic link is fundamental while the environmental influence is of little importance.
You can also read about autism:
- Autism: can be diagnosed as early as 6 months with magnetic resonance imaging
- Autism: knowing is understanding (video)
- The world seen by an autistic person (photo)
- Genes, hormones and the environment: the possible causes of autism
In short, there is still a lot of work to be done on autism and its causes. What is certain is that studies on the causes of autism, and the most varied theses and hypotheses, must not shift attention from the concrete needs of those suffering from autism, families and those who care for them.
Germana Carillo
