How common is autism among close family and friends?

DH's late uncle almost certainly had undiagnosed autism. One of his sons is diagnosed, his other son is NT as far as we know.

My DD has said that she thinks her grandfather (brother of the late uncle) has autistic traits, no one else in the family does.

Yes definitely.
I'm a teacher, and I'd put it at least 4% official diagnosis in my school right now, so probably a much higher percentage of the population.

It is at most 7% across all global populations where ND has been studied, if it was as much as half the world would be more conveniently arranged for ND brains.
”Everyone is a bit ND” is just lazy extrapolation, it’s like saying everyone is a bit left handed because they have two functioning hands.
ND brains are built and arranged differently to NT brains, but we’re all humans. If ND was fully accepted and accommodated in all settings nobody would meet the diagnostic criteria (because diagnosis requires struggle), but ND brains would still be different.

Nobody in my family has been diagnosed with autism but since trying to get a diagnosis for my son, who we’re pretty sure is autistic, I’ve realised that a lot of my family do have autistic traits and may be on the spectrum just not diagnosed, including myself. You won’t always know if family and friends are autistic, especially women as autistic women are diagnosed less often.

I am, my partner is - his dad absolutely is but would never be assessed.

My sister is, my dad again, absolutely is, but would never be assessed, my Mum, possibly, she died at 63 and I don't know what may have been autism masked with alcoholism, or TBI masking autism, or was there never any ASD traits there. She was a very black and white thinker, very blunt, liable to seriously overreact if things were not done her way, or plans change... but lots of things could explain that.

A lot of my friends are, because you do tend to make friends with people on the same wavelength as you, who understand how you think.

Im certain theres loads of people out there who aren't, but then I would be unlikely to be close friends with them!

I have one diagnosised child and one going through assessment and I suspect I’m autistic too.

ND people are more likely to choose to read and comment on threads about autism as they have experience. ND people are more likely to have family members and friends who are ND than NT people.

True, this is based on recorded stats. However, not half population if you're talking autism. I think the highest recorded is over 3% so 50% would be statistically improbable. I do absolutely agree though that it is higher than even the 3%.

Nobody diagnosed but a very strong suspicion with two of the grandparents (always just labelled “a bit odd” or “extremely stubborn” , now much falls into place) and daughter currently being assessed for ADD.
But there is a huge difference between a non-verbal autistic person or one who has physical movements and people who can hold down jobs or marriages but just have strange traits and lack social skills. There is such a spectrum.

They're probably masking. Or they're managing now until they reach burnout

Can I ask what traits make you think you are? (Apart from the genetic links) as I do wonder about myself too, but no one in my family has been diagnosed.

I've got it as has my brother and 2 cousins on our dad's side

I've got several friends with it

But so many autistic people do manage to function well.

Too many to count. But then, when you have a child with autism, who has a friend with autism, and you ran a support group for premature mums, you tend to be around children with autism more than most.

Dh is autistic. Diagnosed at 49 Works full time.
Ds is 19, diagnosed at 3. Also has global delay and severe learning disabilities.
They ate very diffetent!

i think it’s far far higher than this. Possibly even half/half but most are functioning and don’t bother with diagnosis.

My DS is diagnosed as high functioning ASD about 8 years ago (also suspect ADHD but due to lockdowns we didn't purpose a diagnosis for that). My DD has autistic traits also, but refused being diagnosed, so there's nothing official as such for her.

My children's 2 cousins (on his Dad side) are diagnosed autistic, I suspect one of my nephews is autistic, that my eldest brother was as well (he's passed away but would have been in his 70s). DP's Dad (Grandfather to my kids and the 2 cousins) is definitely autistic (but again 70, so no diagnosis).

I am in my fifties. None of my family or my husband’s family or the generation below us have diagnoses. And the sprinkling of new grandchildren don’t have diagnoses either. My friends and their kids do not have autism diagnoses. Maybe I am an anomaly.

3 household members autistic, 2 other wider family members probably autistic. Loads of our friends are diagnosed or likely autistic. It's also highly heritable.

It's most likely to be overlooked in women IMO.

Several friends/children of friends. My dad would probably have been diagnosed if he were in school nowadays.
I'm a primary school SENCO and currently 10% of my school has a diagnosis.

That's according to the National Autistic Society here: https://www.autism.org.uk/advice-and-guidance/what-is-autism
It's unknown the exact figure because, as you rightly point out, there are many people who are undiagnosed but would fall under the diagnostic criteria.
@momtoboys do you suspect you are autistic or some of your family?

DD is autistic, her friends are autistic, a friends husband is autistic.

There is a long line of autism and ADHD through both sides of my family including my own children. I can now look back and identify traits in my long gone grandparents.

Autism rates in the UK are 1-2%. Genetics play a big part and ND people often seek out other ND people so there will be clusters.

I am as are my children, nephew and niece.

When it has a significant impact in functioning.

My eldest is. My youngest obviously is but undiagnosed, my cousin obviously is, and it’s pretty obvious I am too