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Genetic mutation in autism caused by sperm
According to recent study results, the genetic causes of autism are far more complex than previously thought. There are numerous different forms of autism, the causes of which are only partially known. Scientists found that father's sperm are often involved in the autism mutation.
Autism occurs in different forms
Autism is a profound developmental disorder that is considered incurable. Due to the perception and information processing disorder of the brain, autistic people are unable or only partially able to act socially, depending on their severity and severity. This is particularly evident in the contact with their fellow human beings, as they have restrictions in the area of non-verbal communication and have little or no ability to establish informal relationships. In addition, those affected often notice stereotypical behavior. Children who suffer from autism at an early age often do not develop spoken language or are noticeable due to language development delays.
Scientists recently found that the causes of autism are much more complex than previously thought. Instead of fewer genes that trigger the developmental disorder, many small changes in a child's genome act together.
It is particularly interesting that most mutations are not passed on through generations, but only develop in the sperm and egg cells of the parents or in the genome of the child. Three studies were published on this subject in the journal "Nature". The scientists report that autism can therefore be described as an "umbrella disorder". There is not only autism at the molecular level, but numerous different forms, the causes of which differ widely "Like many genetic diseases, autism relies on the activity of many genes," said Mark Daly of the Broad Institute at the Massachusetts Institute of Technology (MIT) in Cambridge, who led one of the studies. When comparing the study results, only three mutations can be identified that could in themselves trigger the developmental disorder. However, the researchers found these genes in less than one percent of autistic children.
Interplay between many small genetic changes leads to autism. During the investigations, the scientists identified more than 200 new point mutations. However, these could not in themselves trigger such severe developmental disorders, they report. However, 49 of the mutated genes are intertwined via a network of proteins that they produce. On the one hand, this network is involved in the formation of brain cells and their connections, on the other hand, it is responsible for regulating the packaging and shape of the DNA genome. The researchers found that genes from this network are often disturbed in autistic children. A common mechanism has not yet been derived. "So far we have only scratched the surface," reports Daly.
The investigations also showed that the paternal genome plays an essential role. The more than 200 autistic children examined showed that they had received three quarters of the mutations from their fathers' sperm. The age of the father is crucial, because the older the father, the higher the likelihood that he will father a child with autism, according to the researchers.
As part of the three studies, the researchers examined families in which a child suffered from the developmental disorder for the first time. This form of autism is called sporadic and is the most common form of developmental disorder. For healthy parents and siblings as well as for autistic children, part of the genome was analyzed, which includes the blueprints for proteins. When evaluating the decoded DNA sequences of the family members, it became clear where the genetic material of the autistic children was disrupted.
Number of autistic people is increasing As the cause of autism is still largely unknown, there is no drug with this indication. Side effects of developmental disorders, which include anxiety, depression and aggressiveness, can be treated with antidepressants or atypical neuroleptics, among other things. Other measures such as occupational therapy, behavioral therapy, training to develop social skills and speech therapy can also help.
As early as 2010, the “Center for Disease Control” (CDC) indicated that the number of autistic people is increasing significantly. Between 2002 and 2006 there was an increase of 57 percent. Some experts see a link between environmental toxins or vaccine supplements and the disease, but there is as yet no sound scientific evidence for this assumption. (ag)
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