In case you're interested and aren't already aware:

UC Davis seems to be investing a bit in ASD research. This one, for instance, focuses on girls:

http://www.ucdmc.ucdavis.edu/mindinstitute/research/gain/ind...

..and there are a few others. Most focus on the intersection of Children and Autism in some form or another.

Alternatively SciAm ran an article a while back around just this issue of how and why we're "missing it" when it comes to recognizing ASD early (or at all) for girls.

https://www.scientificamerican.com/article/autism-it-s-diffe...