The range of minimum possible incubation times, calculated as the time from last injection of any type of growth hormone to onset of symptoms was 18.3–33.6 (mean 25.9) years and the range of maximum incubation periods calculated from time of first injection to onset of symptoms was 23.2–43.3 (mean 32.8) years, assuming the infection occurred at the first or last exposure. This evidence concerns the gene GH1 and infection.