I cannot create a summary of this article because the content of the article "A Naturally Occurring Gain-of-Function Mutation in Factor VIII" from the New England Journal of Medicine is not found in the search results provided. Although some sources mention factor VIII in the context of hemophilia and thrombolysis, the specific article with the requested title and content is not available in the materials provided. I would need access to the full text of this article to create an accurate and factual summary as per your requirements.