Published on 12, July, 2020
I've been making the assumption, possibly incorrectly, that I inherited my autism from my undiagnosed mother.
However, I have just looked at some links and now I'm not sure.
The NHS site says that the causes of autism is unknown:
https://www.nhs.uk/conditions/autism/what-is-autism/
This link talks of a study showing an 80% risk from inherited genes:
https://www.autismspeaks.org/science-news/autism-genetic-study-finds-80-risk-inherited-genes
This earlier article says that children may inherit DNA from fathers who are NOT autistic, but I think (if I'm reading correctly) not from mothers.
https://www.science.org/content/article/autistic-children-may-inherit-dna-mutations-their-fathers
So, I'm a bit confused and would appreciate any clarification.
1. Could we inherit autism from our mothers?
2. With regard to your parents, has either of them been diagnosed?
I believe that some members of the forum are diagnosed and have children diagnosed, so I assume there must be some genetic link.
3. If your parents are/were undiagnosed, has anything led you to believe that one or both of your parents are/were autistic?
Thank you for any input.
There is some evidence that being female creates a sort of genetic buffer to showing autistic traits. This could be linked to having two X chromosomes, rather than the one that males have. X chromosomes have much more genetic information than Y chromosomes, which contain not a lot more than a switch for maleness. There seem to be two main genetic causes of autism, either a few large DNA duplication, deletion or rearrangement events, which often occur in the egg and sperm, so are not inherited from either parent, or by an accumulation of many small DNA variations (often point mutations - single 'letter changes') that are found throughout the population. In the latter case, to be autistic one must inherit more than the average number of these variations, and this can be from one or both parents.
Because of the 'female buffer effect' females require a greater number of autism-linked genetic variants in order to be diagnosable as autistic than males do. In this way a woman who may not be diagnosable as autistic may have sons who are. This female buffering is on top of the systemic under diagnosing of women and girls that is endemic to the diagnostic pathway.
In short, autism traits can be inherited from either parent, but a mother might not show autistic traits as much as a father, though both possess them. Please note that this is from fairly recent research and might not be entirely reliable.
In my own case I can trace a history of 'eccentric traits' and limited sociability to my father, his father and my father's maternal grandfather. My mother, on the other hand, was very sociable indeed, but had some odd traits herself. She may have had hidden autism-linked genetic variants, which contributed to my autism.
I should add that I have two children, one autistic, the other with ADHD (both diagnosed). As I'm autistic, this is not all that surprising, but my wife's sister's children and grandchildren include two people with signs of autism (not yet diagnosed) so my wife may also have more than average numbers of autism-linked genetic variants, though she is allistic herself.
Thank you for that clarification.
Happy to be able to do so. It isn't often a background in genetics is useful in real life.
Invaluable here