Restless Legs Syndrome UK/Ekbom (RLS-UK) We are a registered charity, providing help and support to people living with Restless Legs Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD). Restless Legs Syndrome (RLS), also known as Willis-Ekbom disease, is a neurological disorder characterised by an irresistible urge to move to stop uncomfortable or odd sensations. As it usually interferes with sleep, it is also considered a sleep disorder.