They can be. Sure they can be.
Likely yes, but... Most of what makes us up is hereditary. What varies is which genes one inherits from mother's or father's side, and then how many generations the trait goes back...To the beginning of mankind. I also believe that cultural or tribal traits over thousands of years become part of our genetic makeup. (so don't think faults or hurts come from upbringing: take what ur dealt and make the most out of it.
Why. Why do you care? They are the right size for you. As long as they function properly do not worry.
Syndromes. The first that comes to my mind is turner's syndrome. Affecting females with a single x chromosome.
None. This is a common phenomenon in most cases.
Never knew. There was one.
I have small hands, small feet, my middle bone of my ringfinger is so short that the knuckle is 1 CM more backwards what can it be?
Small bones. Your condition might be a hereditary condition. Ask your parents if somebody in your family have the same condition. I would also want to know if other parts of your body have the same size problem. You might want to take Xrays. Considerations would be dwarfism or Growth Hormone deficiency of a condition known as osteogenesis imperfecta.