Moreover, Janneh et al., (2021) [226] have provided evidence that levels of acid ceramidase are increased in serum of 73% of asymptomatic patients and that reduced sphingosine levels could constitute a sensitive biomarker for the development of symptomatic COVID-19 likely due to its inhibitory action in the binding of Spike protein to ACE2 [227]. This evidence concerns the gene ACE2 and COVID-19.