Despite increasing empirical data to the contrary, it continues to be claimed that morphosyntax and face processing skills of people with Williams syndrome are intact. This purported intactness, which coexists with mental retardation, is used to bolster claims about innately specified, independently functioning modules, as if the atypically developing brain were simply a normal brain with parts intact and parts impaired. Yet this is highly unlikely, given the dynamics of brain development and the fact that in a genetic microdeletion syndrome the brain is developing differently from the moment of conception, throughout embryogenesis, and during postnatal brain growth. In this article, we challenge the intactness assumptions, using evidence from a wide variety of studies of toddlers, children, and adults with Williams syndrome.