Mo. Rev. Stat. § 442.080: Conveyances by persons under eighteen years of age binding, when.

All deeds, mortgages, deeds of trust and other instruments affecting title to real estate hereafter executed by any person under the age of eighteen shall be binding upon such person under the age of eighteen unless he shall file a deed or other instrument duly acknowledged in the office of the recorder of deeds where the land is situate, disaffirming the same, within two years after the disability of the minority is removed.