to some extent the example of sickle cell anaemia can be considered. in this case the normal biconcave shape of rbs(red blood cells or erythrocytes) is mutated to a sickle shape. it is inherited from the parent and thus is a genetic disorder and has a lot of complications for the person carrying the gene. this surely has a fatal effect but on the other hand it makes the person immune to being affected by female Anopheles mosquito that causes malaria.