US citizen based taxation means that all citizens are required to file and pay US income tax, according to their income level filing requirements, regardless of their residence or physical presence in the US. Thereby when a US citizen lives abroad the filing requirement is the same as a taxpayer living in the USA. No exceptions. There is Exclusions and Credits for US citizens living abroad that can be taken advantage but the filing requiremewnts are all the same.

These Individuals May Have Been:
1. Born in the United States but moved permanently from the United States as babies
2. Born in the United States but moved permanently from the United States before reaching the age of majority
3. Born outside the United States to a citizen or citizen(s) of the United States.

Speaking of people born outside the United States to a U.S. citizen parent, one need look no further than U.S. citizenship on Meghan Markel and baby Sussex:
Read full article: www.taxconnections.com/taxblog/what-does-u-s-citizenship-based-taxation-actually-mean-and-to-whom-does-it-actually-apply/