Funding for this research was provided by:
University of Innsbruck and Medical University of Innsbruck
Received: 7 May 2019
Accepted: 13 August 2019
First Online: 13 September 2019
Conflict of interest
: M. Niederreiter, L. Niederreiter, A. Schmiderer, H. Tilg and A. Djanani declare that they have no competing interests.