Some liver diseases may cause porphyria even in the absence of genetic predisposition. Caesar possibly had a genetic predisposition for cardiovascular disease. Numerous studies show a genetic predisposition toward eating disorders. Some people have a genetic predisposition towards developing leukemia. A genetic predisposition may also be a factor. Other risk factors include geographic origin, genetic predisposition, and prior strokes. A family history could indicate a genetic predisposition to melanoma. This may be secondary to a combination of genetic predisposition and environmental factors. Bullying may also result from a genetic predisposition or a brain abnormality in the bully. Multiple pregnancies do not occur from a genetic predisposition. Studies have reported a familial predisposition to myeloma. There is a genetic predisposition to tooth impaction. Genetic predisposition to AS is being investigated. Those with a genetic predisposition may benefit from screening. One conclusion is that there is a genetic predisposition to BPD unrelated to trauma.