Sui generis
Sui generis (; ) is a Latin phrase that means "of its (his, her, their) own kind; in a class by itself; unique."
Syngenic
The word "syngenic" or "syngeneic" (from the Greek word for a relative) means genetically identical, or sufficiently identical and immunologically compatible as to allow for transplantation. For example, it may be used for something transplanted from an identical twin. When the cells are collected from the same patient on whom they will be used, it is called autologous and when collected from identical individuals, it is referred to as syngeneic. A syngeneic graft is known as an isograft.