Mo. Rev. Stat. § 475.357: Child custody and visitation, probate courts to have jurisdiction, when.

The probate divisions of the courts of this state have jurisdiction over issues of the adjudication of incapacity, partial incapacity, disability, or partial disability and the appointment of a guardian, limited guardian, conservator, or limited conservator of an adult eighteen years of age or older whose parents have a pending matter under chapter 210 or * 452 for child custody or visitation of that child. The court that has jurisdiction under chapter 210 or * 452 shall have the authority to enter orders only as to child support after such adjudication and appointment of a guardian by the probate division.