Although many people with restless legs syndrome (RLS) may never be able to identify a cause to their disorder, often it results from other secondary causes. This results in two categories of the condition, primary RLS (of unknown cause) and secondary RLS. There are many conditions that may independently lead to symptoms of RLS.
The first condition that may lead to symptoms of RLS is iron deficiency. The relationship between iron deficiency and RLS symptoms has been extensively studied. In several research studies, low iron levels have been found in the blood and spinal fluid of individuals suffering from RLS. The lower the iron levels, the worse the symptoms. Magnetic resonance imaging (MRI) has shown that the iron content in an area of the brain called the substantia nigra is lower in those with RLS compared to normal individuals, which may contribute to the disorder. In addition, pathological studies have confirmed this change within the brain.
It is therefore recommended that you have your serum ferritin level (a marker of iron stores) checked if you have symptoms of RLS. In addition, a trial of oral iron replacement if the levels are low should be undertaken. Even some individuals with normal levels respond positively to iron replacement.