For example, the model first checks whether IFNL3 is “non-CC” and whether KIR3DS1, KIR2DS1, and HLA-B*44 are all “no.” If these conditions are met for the given patient, the patient is classified as chronic hepatitis C (because from the available data, 25 of the 31 patients who met these conditions were from the chronic hepatitis C class). Here, IFNL3 is linked to chronic hepatitis C virus infection.