Researchers have identified a version of a gene that doubles a person's risk of severe COVID-19 and doubles the risk of death from the disease for people under 60. The gene, LZTFL1, is involved in the regulation of lung cells in response to infection. When the risky version of the gene is present, cells lining the lungs seem to do less to protect themselves from infection with the coronavirus SARS-CoV-2. The gene version that raises COVID-19 risk is present in 60 percent of people of South Asian ancestry, 15 percent of people of European ancestry, 2.4 percent of people with...