Madara and his brother both gained their MS from killing those closest to them. Madara then gained the EMS when he took Izuna's (his brother's) eyes, who had the MS.
Itachi gained his MS when he witnessed Shisui die. Sasuke gained his MS when he learned the truth about Itachi from Tobi. Sasuke then gained the EMS when he took Itachi's eyes.
When Itachi was fighting Sasuke, he was saying how he wanted to take Sasuke's eyes so he could obtain the EMS. Sasuke did not have the MS at the time, so was Itachi lying, or are just "blood tie" Sharingan needed for the EMS? *Sidenote I personally don't believe Itachi would lie about this, because if he did and Sasuke found out, Sasuke would then be questioning Itachi's true motives.
Does anybody have any proof that you have to have the MS in order to awaken the EMS?