The title is definitely an oversimplification. The study it references is really interesting however, because it found strong overlap in this area between developmental stuttering (genetic origin) and neurogenic stuttering (brain injury). There have actually been many neurological differences found between PWS and non-PWS, but those differences are also spread out among the brain, and appear in several different networks. For anyone who's curious, I'd recommend checking out [this paper](https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2019.03088/full), which is highly technical but more accessible than most papers.