Full title: The SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2) in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: analysis of high-throughput genetic, epigenetic, and gene expression studies Abstract Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) show specific epigenetic and gene expression signatures of the disease. However, it is unknown whether these signatures in ME/CFS include abnormal levels of the human angiotensin-converting enzyme ACE and ACE2, the latter being the main receptor described for host-cell invasion by SARS-CoV-2. To investigate that, we first reviewed published case-control genome-wide association studies based on single nucleotide polymorphism data, case-control epigenome-wide association studies based on DNA methylation data, and case-control gene expression studies based on microarray data. From these published studies, we did not find any evidence for a difference between patients with ME/CFS and healthy controls in terms of genetic variation, DNA methylation, and gene expression levels of ACE and ACE2. In line with this evidence, the analysis of a new data set on the ACE/ACE2 gene expression in peripheral blood mononuclear cells did not find any differences between a female cohort of 37 patients and 34 age-matched healthy controls. Future studies should be conducted to extend this investigation to other potential receptors used by SARS-CoV-2. These studies will help researchers and clinicians to better assess the health risk imposed by this virus when infecting patients with this debilitating disease. https://www.medrxiv.org/content/10.1101/2021.03.23.21254175v1.full-text Line breaks added for easier reading.