Alexander obtained his PhD in 2008 on “Establishment and application of array-CGH in clinical genetics and tumor genetics” with 'summa cum laude' from the Rheinische Friedrich-Wilhelms University Bonn, Germany. Throughout his career he has been fascinated use newest technologies to solve clinical research questions. The possibility to identify the genetic cause of human diseases was therefore always a hallmark of his motivation. He has been the first identifying a dominant de novo Mendelian disorder by exome sequencing (Hoischen et al. NatGenet 2010). Similar approaches have resulted in the identification of many disease genes for rare diseases with a focus on developmental disorders. In 2013 He spent 6 months as a visiting scientist in the renowned Department of Genome Sciences (University of Washington, Seattle, USA) and worked in the groups of Prof. Dr. Eichler and Prof. Dr. Shendure. Here he learned the latest technology for accurate and large scale targeted re-sequencing (smMIPs); which he established in Nijmegen after his return. He has established and applied latest genomic technologies which were successfully used in the research of rare diseases, e.g. WES (Hoischen et al. Nat Genet 2010; Hoischen et al. Nat Genet 2011); and MIPs (Ockeloen et al. GiM 2016; Acuna-Hidalgo et al. AJHG 2017; Arts et al. Nat Comm 2017); but importantly were subsequently transferred to routine diagnostics and are still used as diagnostic tools, e.g. WES (de Ligt et al. NEJM 2012); and MIPs (Neveling et al. Clin Chem 2016; Weren et al Hum Mut 2017; Eijkelenboom et al J Mol Diagn).
Since 2013 he is an independent research group leader/PI; to expand on his interest in the genetics of immune diseases (e.g. van de Veerdonk, Plantinga, Hoischen et al. 2011 NEJM); his research group is called ‘Immuno-Genomics’ since January 2017, with a 50% affiliation each at the Department of Internal Medicine and Human Genetics. In the last years he has shown that applications of novel and disruptive technologies will allow new scientific insights and rapid translation into clinical and diagnostic practice at unprecedented speed. Since 2018 he is also a work package leader of the H2020 project SOLVE-RD, in which they aim to identify the cause of unsolved rare diseases using latest (genomic) technologies (www.solve-rd.eu).