GNAS and autosomal dominant cerebellar ataxia: Four (Hosoda et al. 2015; Lee et al. 2014; Singhi et al. 2014; Wu et al. 2011b) and five (Hosoda et al. 2015; Kanda et al. 2013; Lee et al. 2014; Singhi et al. 2014; Wu et al. 2011b) studies addressed KRAS and GNAS mutations between IPMN and serous cystadenoma (SCA) patients, respectively.