I'm a 6'1" man with size 3 feet due to a mild deformity. I've never met another adult with smaller feet.
(lemmings.world)
Was born with super small feet in the 1st percentile as well as hands due to a benign genetic issue. Totally healthy but shoe shopping is always awkward. Have decent balance and can walk and run fine as my calf muscles are quite developed to compensate. No, the myth isn't true.
This is another photo of my foot compared to my friend's size 10 shoe. It's relatively "normal" looking but just shrunk down. And yes, it is a relief that this didn't spread to other areas.