Footnotes

• Contributors SL designed data collection, monitored data collection, and drafted and revised the paper. She is guarantor. FG and CF collected clinical data and AN family history. VC and SB performed general and neurological examination. VR performed the neuropsychological examination. MS and LP revised the literature and the paper. SR performed genetic analysis. SP-B performed the genetic analysis. DM revised the paper. JSS drafted and revised the paper.

• Competing interests None declared.

• Patient consent Obtained.

• Ethics approval Institutional Review Board.

• Provenance and peer review Not commissioned; externally peer reviewed.