Peter Harper, who has died aged 81, was a world expert on the genetics of inherited neurological disorders, particularly Huntington’s disease and muscular dystrophy. He also advocated the idea of genetic counselling – helping people to understand the implications of inherited disorders that might affect them and their families.
Finding a genetic link between the two wasting conditions has led to highly accurate diagnostic and predictive tests for at-risk individuals and their families. Peter played a leading role in that discovery, and in establishing that in both disorders genes have unstable DNA sequences that tend to expand over generations, accounting for the phenomenon of “anticipation”, by which both conditions worsen, and occur at an earlier age, in successive generations. While there is still no remedy, his work has contributed to an understanding of the underlying molecular mechanisms, providing hope that a cure will one day be available.
Peter was born in Barnstaple, Devon, and had what he described as an idyllic semi-rural upbringing as the third child of Richard Harper, a GP, and his wife, Margery (nee Elkington). His father wrote two books on evolution and disease, and his mother held a doctorate in history from the Sorbonne. Interested in natural history from an early age, Peter went from Blundell’s school, Tiverton, to Exeter College, Oxford, where he studied medicine.
He became drawn to genetics at Oxford, and, after clinical studies at St Thomas’ hospital in London, qualified in medicine in 1964, determined to embark on a career combining clinical medicine and genetics. As this was a relatively unusual path at the time, he sought the help of Cyril Clarke, a professor at Liverpool Medical School and one of the few pioneers in Britain of genetics in medicine. Clarke gave him a registrar’s job in his department in 1967, and there Peter met Elaine Abel, a nurse, whom he married in 1968. They had two children, Matthew and Emma, and adopted three more, Nicholas, Katy and Lucy.
In 1969 they went to Baltimore in the US, where Peter undertook a two-year research fellowship with Victor McKusick at Johns Hopkins School of Medicine. He developed a special interest in neurogenetics and carried out a study of myotonic dystrophy, in which half the offspring of a sufferer become affected. This established linkage of the condition to blood group markers called Lu and ABH. The markers and the disorder tended to be co-inherited within families, indicating that they are likely to be close together on the same chromosome, an important first step towards identifying the causative gene.
In late 1971 Peter became a lecturer at the University of Wales College of Medicine (now part of Cardiff University), and eventually established his own medical genetics department as a professor. As well as establishing genetic linkages with neurological conditions, in conjunction with other researchers in the US and mainland Europe he developed a clinical genetics service offering diagnosis and counselling that grew to cover the whole of Wales, and was housed in a new, purpose-built institute in 1985.
Peter’s approach built on the work of Sheldon Reed and others in the US, but placed new emphasis on the involvement of non-medically trained counsellors. In his book Practical Genetic Counselling (1981) he described an approach to advising patients and relatives that helps them to come to their own conclusions about possible future courses of action, rather than be directed by clinicians. He originally intended the book for GPs and non-specialists, but to his surprise it became a standard text for genetic counsellors worldwide, and is now in its eighth edition in many languages.
Peter’s work also became important in attracting other researchers to Cardiff, myself included, and he was pivotal in establishing a world reputation for Cardiff University not only in medical genetics but also in psychiatric genetics.
He retired formally in 2004, the year he was knighted, but continued to work as an emeritus research professor at Cardiff, writing mostly on the history of medical genetics and on ethics. He also maintained an interest in the Genetics and Medicine Historical Network, which he had set up in 2002 in order to make sure that the early history of medical genetics was not lost as its founders retired or died. The last of his six books, Evolution of Medical Genetics – A British Perspective, was published in 2020.
He is survived by Elaine, and their children and seven grandchildren.
• Peter Stanley Harper, medical geneticist, born 28 April 1939; died 23 January 2021