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The clinical presentation of COVID-19 varies from patient to patient and understanding individual genetic susceptibility to the disease is therefore vital to prognosis, prevention, and the development of new treatments. For the first time, Italian scientists have been able to identify the genetic and molecular basis of this susceptibility to infection as well as to the possibility of contracting a more severe form of the disease. The research will be presented to the 53rd annual conference of the European Society of Human Genetics, being held entirely on-line due to the COVID-19 pandemic, today (Saturday).
Professor Alessandra Renieri, Director of the Medical Genetics Unit at the University Hospital of Siena, Italy, will describe her team’s GEN-COVID project to collect genomic samples from COVID patients across the whole of Italy in order to try to identify the genetic bases of the high level of clinical variability they showed. Using whole exome sequencing (WES) to study the first data from 130 COVID patients from Siena and other Tuscan institutions, they were able to uncover a number of common susceptibility genes that were linked to a favourable or unfavourable outcome of infection. “We believe that variations in these genes may determine disease progression,” says Prof Renieri. “To our knowledge, this is the first report on the results of WES in COVID-19.”
Searching for common genes in affected patients against a control group did not give statistically significant results with the exception of a few genes. So the researchers decided to treat each patient as an independent case, following the example of autism spectrum disorder. “In this way we were able to identify for each patient an average of three pathogenic (disease-causing) mutations involved in susceptibility to COVID infection,” says Prof Renieri. “This result was not unexpected, since we already knew from studies of twins that COVID-19 has a strong genetic basis.”
Although presentation of COVID is different in each individual, this does not rule out the possibility of the same treatment being effective in many cases. “The model we are proposing includes common genes and our results point to some of them. For example, ACE2 remains one of the major targets. All our COVID patients have an intact ACE2 protein, and the biological pathway involving this gene remains a major focus for drug development,” says Prof Renieri. ACE2 is an enzyme attached to the outer surface of several organs, including the lungs, that lowers blood pressure. It serves as an entry point for some coronaviruses, including COVID-19.
 European Society of Human Genetics