Since both VPS13A and XK disease are very rare diseases with an estimated incidence of 1:1,000,000 and 1:10,000,000, respectively, we used the occasion of the ‘11th International Meeting on Neuroacanthocytosis Syndromes’ (Kaestner, 2023), which was a joint scientific and patient meeting, to recruit two VPS13A disease patients and four XK disease patients as well as three VPS13A and four XK mutation carriers. Here, XK is linked to neuroacanthocytosis.