Case Report: Death Due to Novel Coronavirus Disease (COVID-19) in Three Brothers. We report fatal cases of novel coronavirus disease (COVID-19) in three brothers in Iran. An increased susceptibility to specific pathogens has been reported for a number of genetic defects. Considering the fact that most of them who are affected by COVID-19 recover, deaths in three brothers who lived separately and had no known underlying disease suggest genetic predisposition to COVID-19 in some individuals.