Studies have shown that TLR7 expression levels and activity are lower in males, the elderly, or people with underlying diseases such as obesity, who are more susceptible populations to SARS-CoV-253,54, suggesting a potential association between susceptibility to SARS-CoV-2 and TLR7 expression levels and activities. The gene discussed is TLR7; the disease is obesity due to melanocortin 4 receptor deficiency.