A dopamine imbalance that affects muscle movements may be the underlying reason for restless leg syndrome, but the definitive causative factor is usually not known, according to Mayo Clinic. Abnormalities in the automatic movement-controlling portion of the central nervous system may be the source, but research is ongoing, adds WebMD.
Restless leg syndrome, or RLS, may have a genetic component; individuals with a familial predisposition experience the onset of the condition at a younger age, usually before age 50, reports Mayo Clinic. The condition is more common in women than men, and the incidences of onset increase with age, although even children can experience RLS. Pregnancy can often catalyze the disorder, especially during the last trimester, with the condition receding after the birth.
RLS often appears in conjunction with the nerve damage diabetics suffer in extremities, called peripheral neuropathy, notes Mayo Clinic. Kidney failure and the frequently resulting iron deficiency can trigger or worsen RLS. Varicose veins are often present in individuals with RLS, and those suffering from Lyme disease and fibromyalgia can experience the condition more frequently, reports WebMD. A vitamin B-12 or magnesium deficiency can be a precursor to RLS, as can rheumatoid arthritis and spinal nerve injury. The use of caffeine, alcohol and certain medications, such as anticonvulsants, antipsychotics and antidepressants, are often linked to RLS.