Add the follow code to the functions.php
. Comment out the lines of layouts you want to keep active.
/** Unregister layout settings */
genesis_unregister_layout( 'content-sidebar' );
genesis_unregister_layout( 'sidebar-content' );
genesis_unregister_layout( 'content-sidebar-sidebar' );
genesis_unregister_layout( 'sidebar-sidebar-content' );
genesis_unregister_layout( 'sidebar-content-sidebar' );
genesis_unregister_layout( 'full-width-content' );