Dr. Thomas Liehr, a biologist (diploma, PhD and postdoctoral degree in human genetics), has been working in molecular cytogenetics since 1991. He has been head of the molecular cytogenetic group at the Institute of Human Genetics, Jena, Germany since 1998; before he was a PhD fellow of the Herbert Quandt Stiftung der VARTA-AG at the Institute of Human Genetics, Erlangen, Germany. Working intensively in diagnostics, since 2002 he has been a ‘specialist in human genetics diagnostics’ (FHG = Fachhumangenetiker), a title awarded by the German Society of Human Genetics (GfH), and a European registered Clinical Laboratory Geneticist (ErCLG) since 2015. Dr. Liehr’s research fields include clinical genetics, leukemia cytogenetics and the (3D) structures of the interphase and the human chromosomes, as well as breakpoint characterization. The results of his research have been published in 5 books, >50 book chapters, >550 peer-reviewed papers, and ~800 abstracts. His particular expertiseis molecular cytogenetics including chromosomal heteromorphisms, small supernumerary marker chromosomes (sSMC) and uniparental disomy, fields for which he has collected all available literature and made it freely available on the Internet. Further, Dr. Liehr has multiple longstanding international collaborations with many scientists around the world including researchers in e.g. Armenia, Croatia, India, Morocco, Russia, Serbia, Thailand, and Brazil.