Scientists have identified a rare genetic condition that causes people to age at a significantly faster rate than normal. Named Heyn-Sproul-Jackson syndrome, the disorder leads to rapid cellular deterioration and triggers age-related health complications much earlier in life. The study, conducted by the University of Edinburgh and published in the journal Nature Genetics, could open the door to future research that advances understanding of how our bodies age, helps prevent age-related illness, and explores whether it is possible to reverse these changes.
Discovery of the Epigenetic Clock
Professor Andrew Jackson, the study's lead researcher from the Institute of Genetics and Cancer, said: "It has been exciting to be able to discover a rare human genetic disorder, that helps us understand this clock's role for all our long-term health in old-age." The international team of scientists examined DNA methylation, a natural process that leaves markers on DNA over time. Also referred to as the epigenetic clock or biological clock, it is present in every cell in the body and measures ageing not by the number of years lived, but by the condition and functionality of the cells themselves.
How the Clock Ticks
This clock ticks at varying rates depending on lifespan. For instance, animals with a shorter life expectancy than humans have a DNA methylation clock that ticks considerably faster. Until now, researchers were uncertain whether this biological clock simply tracked time within the body or whether it also played a role in the ageing process itself. In the newly discovered Heyn-Sproul-Jackson syndrome, methylation marks appear on the same spots on DNA as normal ageing, but at a considerably faster rate.
Link to Age-Related Diseases
The new study also succeeded in linking DNA methylation to multiple age-related disease processes. These included a reduction in blood cell production, which is associated with greater vulnerability to infections, as well as osteoporosis and hair loss. Using mouse models, scientists discovered that increasing DNA methylation marks triggered changes in metabolism typically associated with diabetes and high cholesterol. As the marks continued to build up, adult stem cells that the body relies upon to repair and regenerate tissues began to fail. The researchers believe this could account for the deterioration in tissue function that is connected to disease as we age.
Future Research Directions
The research team has further studies planned to shed light on how DNA methylation contributes to reduced tissue renewal, and to determine whether these changes can be reversed. Professor Jackson said: "That marks on someone's DNA can precisely predict their age has fascinated me for a long time. This study has only been possible because of very many generous, often co-located colleagues, who contributed their diverse skills to this work."
Professor Joris Veltman, Director of the Institute of Genetics and Cancer, said: "By studying a rare disease in depth, our colleagues have gained new insight into the biology of human ageing and identified promising directions for future rejuvenation therapies. This study shows the power of international collaboration, bringing together 76 researchers from seven countries."
