Mississippi Code Annotated section 43-21-151 (Rev. 2015) provides, in the relevant part that:
(1) The youth court shall have exclusive original jurisdiction in all proceedings concerning a delinquent child, a child in need of supervision, a neglected child, an abused child or a dependent child except in the following circumstances:
(a) Any act attempted or committed by a child, which if committed by an adult would be punishable under state or federal law by life imprisonment or death, will be in the original jurisdiction of the circuit court;
(b) Any act attempted or committed by a child with the use of a deadly weapon, the carrying of which concealed is prohibited by [s]ection 97-37-1, or a shotgun or a rifle, which would be a felony if committed by an adult, will be in the original jurisdiction of the circuit court[.]
The statute deals with some very narrow exceptions where a crime can be tried in Youth Court as opposed to Circuit Court. The Court of Appeals recently vacated a jury verdict where the State skipped getting the case transferred from Youth Court. A link to the opinion is here.