Well, I am nearly certain my brother's condition is related to FAS (Fetal Alcoholic Syndrome) due to our mother's increasing use of whiskey and there must also be something to her smoking (I call them 'monoxide brains') while he was in the womb. There is a link between smoking and Crohn's and I am certain this exacerbated her undiagnosed AS, but absolutely led to her death at age 42 from aortitis and inflammatory cascade causing stroke.
As far as I know, I am only Irish, English, and Scots; a rather too narrow mix, I suppose.
My brother's P-S could be articulated around age 8, but certainly he had an "acute strangeness" since birth.
I suppose there are some things that city dwellers are more prone to. As a child I had terrible allergies and when I went to cousin's farm I nearly died haying a field once!