The identification of mutations in genes such asSNCA(α-synuclein),LRRK2(leucine-rich repeat kinase-2), orGBA1(glucocerebrosidase) has allowed a better understanding of the molecular and pathophysiological mechanisms of the hereditary forms and of PD in general.63However, although there are currently 25 genetically linked subtypes of PD, genetic testing in clinical practice (single genetic testing or Sanger; genetic panel; or exome sequencing) should only recommended for a minority of patients presenting the following features:. The gene discussed is GBA1; the disease is Parkinson disease.