Mo. Rev. Stat. § 456.4-402
1. Other than for a trust created by section 475.092, 475.093, or 511.030, or 42 U.S.C. Section 1396p(d)(4), a trust is created only if:
(3) the trust has a definite beneficiary or is:
(L. 2004 H.B. 1511, A.L. 2006 S.B. 892)