(1) The effects of a disclaimer are:

(a) If property or an interest therein devolves to a disclaimant under a testamentary instrument, under a power of appointment exercised by a testamentary instrument, or under the laws of intestacy, and the decedent has not provided for another disposition of that interest, should it be disclaimed, or of disclaimed or failed interests in general, the disclaimed interest devolves as if the disclaimant had predeceased the decedent, but if by law or under the testamentary instrument the descendants of the disclaimant would take the disclaimant’s share by representation were the disclaimant to predecease the decedent, then the disclaimed interest passes by representation to the descendants of the disclaimant who survive the decedent. A future interest that takes effect in possession or enjoyment after the termination of the estate or interest disclaimed takes effect as if the disclaimant had predeceased the decedent. A disclaimer relates back for all purposes to the date of death of the decedent.

(b) If property or an interest therein devolves to a disclaimant under a nontestamentary instrument or contract and the instrument or contract does not provide for another disposition of that interest, should it be disclaimed, or of disclaimed or failed interests in general, the disclaimed interest devolves as if the disclaimant had predeceased the effective date of the instrument or contract, but if by law or under the nontestamentary instrument or contract the descendants of the disclaimant would take the disclaimant’s share by representation were the disclaimant to predecease the effective date of the instrument, then the disclaimed interest passes by representation to the descendants of the disclaimant who survive the effective date of the instrument. A disclaimer relates back for all purposes to that date. A future interest that takes effect in possession or enjoyment at or after the termination of the disclaimed interest takes effect as if the disclaimant had died before the effective date of the instrument or contract that transferred the disclaimed interest.

(2) The disclaimer or the written waiver of the right to disclaim is binding upon the disclaimant or person waiving and all persons claiming through or under either of them.