In this study of chorea-acanthocytosis (ChAc), Amini and colleagues describe detailed clinical characteristics of 23 people from 16 families with this rare genetic disease. ^{Reference Amini, Rohani and Jafarabadi Ashtiani1} Though small cross-sectional samples should be interpreted carefully, their consistent collection of detailed measures in such a rare disease is a commendable effort.

Also known as VPS13A disease, these findings highlight how neither moniker adequately captures the range of symptoms occurring in ChAc. Chorea and acanthocytosis are neither necessary nor sufficient to define the disorder, ^{Reference Peikert, Dobson-Stone and Rampoldi2} and in this sample, dystonia was nearly as common, particularly eating dystonia with lip or tongue biting in two-thirds. Oculomotor abnormalities were found in more than three quarters of this sample, particularly affecting vertical saccades and smooth pursuit. ^{Reference Amini, Rohani and Jafarabadi Ashtiani1} Eye movement abnormalities have been described in ChAc, ^{Reference Gradstein, Danek, Grafman and Fitzgibbon3} but this level of detail is of value to clinicians.

There is also emphasis on nonmotor symptoms and functional measures to place the findings in context. Detailed information about neuropsychiatric symptoms is presented, including much higher rates of suicidal ideation than in previous reports. ^{Reference Walker, Miranda, Jung and Danek4} Their systematic assessment of olfactory dysfunction in VPS13A disease is novel, with half of twenty cognitively eligible participants meeting criteria for hyposmia. Further, they report a correlation of hyposmia and cognitive impairment may be informative about pathogenesis and aligns with findings in other disease populations. ^{Reference Jacobson, Vilarello and Tervo5} As olfactory testing is widely available and inexpensive, this presents an avenue for further collaborative study.

The study illustrates how rare-disease knowledge advances: case reports can show what is possible by illustrating unique clinical phenomena, and diligent clinical efforts show their patterns, range, and proportions. This textured understanding can sometimes lead to new hypotheses, multicentre collaborations, or broaden our view of a disease beyond its name.