A 1-base pair (bp) insertion in the DPP7 gene destroying DPP7 transcription may have a potential monogenic effect for asymptomatic COVID-19 in a Chinese family analysis.106 DPP7 known as a survival factor to maintain lymphocytes quiescently may potentially involve in COVID-19 immunopathogenesis.140 The specific functional effects of the DPP7 gene in COVID-19 still need further clarification. Here, DPP7 is linked to COVID-19.