“…A high aggregation of fibromyalgia in families was demonstrated [45]. Using self-reporting of chronic widespread pain (CWP) as a surrogate marker for fibromyalgia, the Swedish Twin Registry reports monozygotic twins with CWP have a 15%, and Dizygotic 7%, increased chance of having CWP [46,47]. However, the mode of inheritance is most probably polygenic [36].…”