To date, only six of 20 mutations of this gene have been demonstrated to be pathogenic (Figure 1), and the most common mutation of LRRK2 gene is G2019S (accounting for 5–6% of familial PD, and in 1–2% of sporadic cases), whose importance lies not only in its relatively high frequency in specific populations but also its association with late-onset sporadic ‘classical’ PD[2]. This evidence concerns the gene LRRK2 and Parkinson disease.