Non-Lifestyle related diseases
So the CDC has a list of total leading causes of death

https://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm


  Number of deaths for leading causes of death 
  • Heart disease: 614,348 
  • Cancer: 591,699 
  • Chronic lower respiratory diseases: 147,101 
  • Accidents (unintentional injuries): 136,053 
  • Stroke (cerebrovascular diseases): 133,103 
  • Alzheimer's disease: 93,541 
  • Diabetes: 76,488 
  • Influenza and pneumonia: 55,227 
  • Nephritis, nephrotic syndrome, and nephrosis: 48,146 
  • Intentional self-harm (suicide): 42,773 


Cancers can be further subdivided into types which may or may not be related to lifestyle. There are lung cancers and skin cancers that are not linked to smoking or skin damage respectively. Cancer is very complicated.

Most of the causes on this list have lifestyle or environmental components to them. Influenza and pneumonia have less to do with lifestyle and more to do with the immune system either being too robust or not robust enough but the immune system is influenced by lifestyle as well. 

To get a list of diseases that are the leading causes of death and not influenced by lifestyle or environmental, you'd probably be looking at genetic diseases like cystic fibrosis for example. 

The WHO has a list of these monogenetic diseases. These are diseases that are caused by a single gene (either one or two copies of the gene depending on the disease) and are independent of lifestyle and environment.


  Thalassaemia 
  Sickle cell anemia 
  Haemophilia 
  Cystic Fibrosis 
  Tay sachs disease 
  Fragile X syndrome 
  Huntington's disease 


You can read more about these diseases here: http://www.who.int/genomics/public/geneticdiseases/en/index2.html