Mo. Rev. Stat. § 475.357

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.