U1 and atypical hemolytic-uremic syndrome: A 30-year-old male with a past medical history of COVID-19 infection, cytomegalovirus-associated sepsis, and atypical hemolytic uremic syndrome (aHUS), as well as concern for mixed connective tissue disease with positive anti-U1 ribonucleoprotein antibodies, presented to the hospital with fatigue and shortness of breath.