Recent studies also showed that genetic variants of leucine-rich repeat and Ig domain containing 1 (LINGO-1) gene could be risk factor for ET (Zhou et al., 2012) and polymorphism of leucine-rich repeat and Ig domain containing 2 (LINGO-2) is associated with risk of PD (Su et al., 2012). This evidence concerns the gene LINGO1 and Parkinson disease.