How do Catholics explain hereditary diseases?

The short list of hereditary diseases includes color blindness, down syndrome, hemophilia, sickle cell disease, and albinism. The short list of sexually transmitted diseases includes chancroid, chlamydia, gonorrhea, herpes, HIV/AIDS, human papillomavirus/genital warts and syphilis. All of these diseases require that another person has previously had them, either your parents or your sexual partner. Humanity begins with Adam and Eve, who must have carried all of these diseases to pass them on to their offspring. Did God created Adam and Eve loaded with all those diseases? How do Catholics explain this situation?