H3-3A and COVID-19: More specifically, we have found that myocardial development-associated proteins including those involved in sarcomere organization (CSRP3, SYNPO2L, LDB3, and MYPN) and muscle cell differentiation (SPEG, QKI, and H3-3A) were downregulated in the COVID-19 patient heart tissues, indicating the structure of the heart may be affected.