Variant of parent polypeptide comprising the Fc region, polypeptide comprising a variant of the Fc region with altered binding affinity of Fc gamma receptor (FcγR), a polypeptide comprising the variant of Fc region with altered binding affinity of neonatal Fc receptor (FcRn), a composition, isolated nucleic acid, vector, host cell, method for preparing the polypeptide variant, the use of the polypeptide variant and method for preparing a the Fc region variant