Since 2013, he has been Professor of Functional Genetics and Human Genetics at the Institute of Human Genetics at the University of Lübeck. In addition to genetic and functional analysis in the field of cohesinopathies (like Cornelia de Lange syndrome), the research of his research group focuses on molecular mechanisms in the area of genetic disorders and hereditary diseases. 

He studied biology at the Ruhr-University Bochum. In his doctorate and postdoctoral studies at the Institute of Human Genetics in Essen, he performed functional analysis of the transcription factor TRPS1. 

David has been a consultant in paediatric genetics in Edinburgh since 1994. His clinical interests are in paediatric neurodevelopmental disorders and in the identification of genetic causes of serious developmental disorders.

He studied medicine at University of Edinburgh and then trained in paediatrics in Edinburgh, Bristol and Glasgow. He trained in clinical genetics in Glasgow as a Wellcome Trust Clinical Research Fellow and in Johns Hopkins Hospital in Baltimore on a Howard Hughes Medical Institute Clinical Research Fellowship. 

He did his PhD in Cell and Molecular Biology and is an attending physician and Associate Medical Director of the Roberts Individualized Medical Genetics Center at Children's Hospital of Philadelphia. 

He did his medical specialist training in Pediatrics at Children's Hospital of Philadelphia, followed by a fellowship in genetics at Children's Hospital of Philadelphia & University of Pennsylvania.