Family Ties risk Factors Relationship Risk Monozygotic twins 40-50% Dizygotic twins 17% Children 13% Siblings 10% Half siblings 6% Grandchildren 5% Nieces, Nephews% Aunts, Uncles, cousins 2% General Population 1%Relationship Risk Monozygotic twins 40-50% Dizygotic twins 17% Children 13% Siblings 10% Half siblings 6% Grandchildren 5% Nieces, Nephews 4% Aunts, Uncles, Cousins 2% General Population 1%