FGF20 and Parkinson disease: Unfortunately, linkage of the SNP in the 3′UTR of FGF20 could not be replicated in a Spanish population of 512 PD patients and 258 healthy controls (de Mena et al., 2010a) while the original study collected samples from PD centers in the U.S. In another study, a specific miR-133b homozygous variation could be found at a higher frequency in PD patients (6/575) than controls (0/650), but could not be confirmed in a second set of patients (1/250) vs. (2/210) controls (de Mena e tal., 2010b).