Ismaili

Ismaili Shia (or Ismailiya; ) are a Shia Muslim sect. They are different from the usual Shia Islam because they do not agree on who the 7th Imam, or religiousleader is. Unlike other Shia Muslims, they believe that Ismail ibn Jafar was the 7th Imam. Most Shia Muslims believe that Musa ibn Jafar was the 7th Imam. Ismail died when his father, Jafar ibn Muhammad the 6th Imam was still alive. They believed that Ismail's son Muhammad was the next Imam and deserted the sixth Imam. 
They are split into several sects. The biggest of these are the Nizaris. They are led by the 49th Imam Aga Khan, another title of the Ismaili Imams. The current Aga Khan is Karim Al Hussaini.