SNCA and Parkinson disease: A growing body of clinicalstudies have proposed that idiopathic RBD is a risk factor for the development ofabnormal alpha-synuclein mediating neurodegenerative diseases (Parkinson’s disease -PD, multisystem atrophy - MSA or Lewy body disease - LBD), with an estimated rate ofphenoconversion over a lifetime of 81 to 90%9.