ACE2 and obesity due to melanocortin 4 receptor deficiency: Morbid obesity may also cause a decrease in the lungs’ functional residual capacity, causing hypoxemia, while the expression of angiotensin-converting enzyme 2 (ACE2) from the adipose tissue also has a high affinity to SARS-CoV-2, which may increase the virality of COVID-19 [26–30].