There are definitely Alans still around. One of the most famous is Alan Tudky, who was in Rogue One:

http://www.imdb.com/name/nm0876138/?ref_=nv_sr_1

Now, being serious for a moment, the Alans are still present and are called Ossetians. Ossetian is an Eastern Iranian language and is a descended from ancient Alanian:

http://www.iranicaonline.org/articles/ossetic

Now, in regards to "white", one must remember that the idea of "white" did not exist in the ancient period. We can certainly say that, based on where they lived, they would have had certain common features in terms of appearance, but to describe them as "white" or "European" is wrong. For example, many one of the major genetic haplogroups of Europe is R1A:

https://en.wikipedia.org/wiki/File:Haplogroup_R1b_(Y-DNA).PNG

Notice something interesting in the map? There is a concentration of a variation of R1B in Sub-Saharan Africa! So there is an African population that is genetically related to Europe but looks completely and utterly different! You cannot strictly associate appearance with "blood".