Is Kim Jong-un's sister Kim Yo-jong a potential successor?

North Korea has never publicized who would follow leader Kim Jong Un in the event he is incapacitated, and with no details known about his young children, analysts say his sister and loyalists could form a regency until a successor is old enough to take over. South Korean and Chinese officials on Tuesday (April 21) cast doubt on reports that Kim was gravely ill following a cardiovascular procedure, after his absence from a key state anniversary event triggered speculation about his health.