GBA1 and Parkinson disease: Nalls et al. (2019) used SKAT-O in their meta GWAS to identify genes with two or more rare coding variants, and 7 significant genes: LRRK2, GBA, CATSPER3, LAMB2, LOC442028, NFKB2 and SCARB2. SKAT has also been used to study the association of genetic variants to individual phenotypic characteristics of PD, including motor and cognitive functions (Markopoulou et al., 2021).