Increased prevalence of restless legs syndrome in narcoleptic patients

Background: It has been repeatedly documented that there is an increased prevalence of periodic leg movements in patients with narcolepsy. Comparatively less is known about the incidence of restless legs syndrome (RLS) in these patients. AIMS and Methods: At the annual meeting of the Deutsche Narkolepsie Gesellschaft (DNG e.V.) we collected blood samples after overnight fastening and questionnaire data that included a RLS questionnaire exploring the four mandatory symptoms (yes/no), the age at first occurrence and family history. Results: 57 subjects answered the RLS questionnaire (39F, 18M, 48±17 y). Ten females (26%) and 4 males (22%) confirmed all four RLS criteria. RLS-positive subjects did not differ from RLS-negative subjects in terms of age, intake of SSRIs (14% in both groups) or tricyclic antidepressives (9 vs. 14%). Serum levels of iron, ferritin, and transferring did not differ between RLS-positive and RLS-negative narcoleptic patients. To date, the diagnosis of narcolepsy could be confirmed in 39 subjects (28F 11M, 46±17y) by contacting physicians and sleep laboratories. In this group 6 females (21%) and 3 males (27%) were RLS positive and again did not differ from RLS-negative subjects in age. Age at first occurrence of symptoms was provided by 8 subjects and was ≤35 y in 5 (56%) and ≤45 y in 6 (67%). Conclusion: In our sample of German subjects with narcolepsy we found a high prevalence of RLS with an early age of onset.