Received: 10 September 2018
Accepted: 26 November 2018
First Online: 18 December 2018
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of the Medical Faculty of Heidelberg (reference number S-523/2012). All patients and healthy controls were fully informed of the aim of the study, and written informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.