If your born with this cholesterol problem, then i imagine your cholesterol would be high as a child, therefore applying the same or similar risk as a teen or adult....
Bear in mind the amount of crap a child can eat.....when i was a child it was breakfast of any cereal (eg frosties with full fat milk),lunch- school dinners(eg chips, meat,beans - high sugar pudding), sweets,chocolates,fizzy drinks,evening meal(eg meat and 2/3 veg and a pudding),
So if high cholesterol thickens blood- sticks to arteries, causes blockages thus leading to heart attacks and strokes, how come it is only a high risk once discovered as an adult???