Originally Posted by catalinusd
Can tell me anyone if there are any byzantine family left in modern Istanbul or all of them emigrated?
Do you mean any of the descendants of the Palaiologos Dynasty? I couldn't pinpoint exact people but there definitely are descendants of the family in Turkey, including Istanbul.
Many members of the Palaiologos family inter-married with most Royal and Noble Houses of the region (Ottoman, Bulgarian, Georgian, Armenian, Serbian) so yes there are numerous descendants. Some of the Ottoman Royals are descended from Palaiologos dynasty as well through matrilineal lines, and quite a few of them live in Istanbul.
If you mean members of the Byzantine Imperial Family, I am not sure one exists as such any more.