Tex. Property Code § 240.053

(a) If a trustee disclaims an interest in property that otherwise would have become trust property:

(1) the interest does not become trust property;

(2) the disclaimer:

(A) takes effect as of the time the trust became irrevocable; and

(B) relates back for all purposes to the time the trust became irrevocable; and

(3) the disclaimed interest is not subject to the claims of any creditor of the trustee, the trust, or any trust beneficiary.

(b) If the instrument creating the disclaimed interest contains a provision that provides for the disposition of the interest if the interest were to be disclaimed, the disclaimed interest passes according to that provision.

(c) If the instrument creating the disclaimed interest does not contain a provision described by Subsection (b), the disclaimed interest passes as if:

(1) all of the current beneficiaries, presumptive remainder beneficiaries, and contingent beneficiaries of the trust affected by the disclaimer who are individuals died before the trust became irrevocable; and

(2) all beneficiaries of the trust affected by the disclaimer who are not individuals ceased to exist without successor organizations and without substitution of beneficiaries under the cy pres doctrine before the trust became irrevocable.

(d) Subsection (c) applies only for purposes of determining the disposition of an interest in property disclaimed by a trustee that otherwise would have become trust property and applies only with respect to the trust affected by the disclaimer. Subsection (c) does not apply with respect to other trusts governed by the instrument and does not apply for other purposes under the instrument or under the laws of intestacy.