hsa-mir-4257: Hsa-mir-4257 is a microRNA that is downregulated in mild COVID-19 cases compared to healthy controls and further downregulated in severe COVID-19 cases compared to mild cases [PMC8625524]. It has been identified as an independent prognostic factor for COVID-19 severity, along with other factors such as LncRNA RP11-773H22.4, IL11RA mRNA, and IL11RA protein levels [PMC8625524]. Hsa-mir-4257 has shown better sensitivity in predicting COVID-19 severity compared to ferritin and procalcitonin [PMC8625524]. SARS-CoV-2 infection leads to the upregulation of LncRNA RP11-773H22.4, which in turn downregulates hsa-mir-4257 and upregulates IL11RA mRNA [PMC8625524]. Hsa-mir-4257 is negatively correlated with IL11RA mRNA expression [PMC8625524]. It has been found to be discriminatory between COVID-19-positive patients and healthy controls, as well as between mild and severe cases of COVID-19 [PMC8625524]. In the context of T1D, hsa-mir-4257 has been identified as a potential biomarker associated with the development of the disease along with other genes such as PRKACA, DSP, RGS4, FOXD1, EYA1, TFAP2A, and GAB2 [PMC8028841]. In addition, hsa-mir-4257 has been found to have a binding site on Omicron's Spike NTD due to a stretch of nucleotide insertion [PMC9721271]. Treatment with ß-methyl-digoxin leads to the downregulation of hsa-mir-4257 [PMC5355295].