Scientists have linked certain genes to restless legs syndrome, suggesting the twitching condition described as “jimmy legs” in a “Seinfeld” episode is biologically based and not an imaginary disorder.

New studies published this week in two top medical journals are being called the first to identify specific genes responsible for restless legs syndrome symptoms. Research in the New England Journal of Medicine, linked a common gene variation to nighttime leg-twitching. It involved people in Iceland and the United States.