On the prevalence and symptoms of adults with genetic neurodevelopmental disorders and normal range intellectual functioning: a case-based discussion

Within the last twenty-five years, there has been an unprecedented increase in the number of known genetic neurodevelopmental disorders. Currently there are over three thousand known conditions, but diagnosis of such conditions in adults remains uncommon compared to pediatric populations and consequently there is little knowledge about the health effects of these conditions in adults. In our practice we have observed that many adults with neurodevelopmental conditions are not intellectually disabled by existing standards, yet they endure cognitive limitations and poorer overall health compared to unaffected individuals. In this discussion, we review notable cases that demonstrate a pattern of symptoms that we think typify a subset of adults with neurodevelopmental disorders and normal-range intellectual functioning.