Childhood-onset restless legs syndrome.

The clinical characteristics of childhood-onset restless legs syndrome are described. Thirty-two of 538 subjects (5.9%) examined in our sleep disorders center received diagnoses of restless legs syndrome. They were classified based on published criteria into probable (n = 9/32 or 28%) and definite (n = 23/32 or 78%) categories. Apart from an earlier age of diagnosis of the probable group, no differences were found between the two categories. Sleep onset or sleep maintenance insomnia was the most common symptoms, being present in 28 of 32 subjects (87.5%). Inattentiveness was seen in 8 of 32 subjects (25%). Serum ferritin levels were measured in 24 of 32 subjects and were below 50 microg/L in 20 of 24 subjects (83%). A family history of restless legs syndrome was present in 23 of 32 (72%) subjects, with mothers almost three times more likely to be affected than fathers (p = 0.02). We conclude that iron deficiency and a strong family history are characteristic of childhood-onset restless legs syndrome.