This update on restless legs syndrome (RLS) focuses on its pathophysiology, genetics, health impact, and treatment. Although symptoms are exquisitely responsive to dopaminergics, clear delineation of dopaminergic pathology has not emerged. Rather, heuristic models of alterations in spinal sensorimotor circuits and central nervous system iron deficiency are gaining more attention. Genome-wide association studies have recently identified polymorphisms in three genes with no obvious relationship to dopamine that account for 70% of the population risk for RLS. A single variant in the BTBD9 gene on chromosome 6 contributes to 50% of the population risk. Although the functions of BTBD9 remain uncertain, its biological plausibility is evidenced by its dose-dependent relationship to periodic limb movements of sleep, decrements in iron stores, and ethnic differences in RLS prevalence. RLS is also implicated in cardiovascular morbidity. Despite these advances in our knowledge, there remain unanswered questions about the pathophysiology of RLS as well as its genetics, health-related significance, and treatment.

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Purpose: The aim of this survey was to gather data about the incidence of various sleep disorders, particularly sleep apnea, in subjects with IPF who participated in a regional patient-oriented seminar on this condition. We hypothesized that the frequency of Obstructive Sleep Apnea (OSA) and psychiatric sleep disorders would be disproportionately high in the IPF population. Methods:The project was a one-time survey administered to stable patients with IPF and their family members from the South eastern USA who participated in the "Living with IPF" public seminar at the Emory University campus. The survey used a validated questionnaire, i.e., Sleep Disorders Questionnaire (SDQ), to detect presence of Sleep Apnea (SA) and selected sleep disorders -Restless Legs Syndrome (RLS), Psychiatric Sleep Disorders (PSY) and narcolepsy (NAR). The questionnaire was administered to all participants (with and without IPF), in a confidential manner. The findings were used to determine if there were differences in the incidence of SA and other sleep disorders between individuals with IPF and those without the disease.Results: A total of 52 people agreed to participate in the study. One subject was excluded due to unclear IPF status. The median SDQ raw scores in IPF patients for SA, RLS, PSY and NAR were 28.7, 27.1, 26.2 and 26.5, respectively; overall, they were not statistically different in IPF patients versus control subjects. However, as validated in other studies, patients with history of OSA had significantly higher SDQ-SA scores. Conclusions:The present study aimed to investigate cross-sectionally the incidence of self-reported sleep conditions in patients with IPF versus healthy family member controls. Overall, we did not find a disproportionately higher incidence of sleep disorders in the IPF population. This may be explained by inherent methodological limitations and the small sample size.