Can a nobody write a serious book?

My current work in progress is a nonfiction reference book on rare genetic diseases. You can scroll down a bit to read about it.  I've gotten some feedback from folks who "don't want to discourage me" but who warn me that without being a doctor or some specialist I don't have a chance of this book taking off.  I beg to differ.

It's very easy these days for celebrities to get a book published.  They bring with them name recognition so that even if they are writing something off the topic of their own celebrity, people will still buy their book.  Hence the proliferation of children's books and how-to books by celebrities. And I acknowledge that having a name helps sell books.  I also understand that medical books need the gravitas that specialists in the field provide.

The problem is that no one - no celebrity and no medical specialist - is writing this book. There is no book.  There are numerous academic papers written by very credible scientists and doctors.  But there is no book.  There is information online, but a lot of it is old and invalidated by more recent research. What is needed is a kind of manual for families and quick reference for front-line doctors.

Do I believe this will be easy?  No.  I've been a writer all my life and I understand the kind of research and hard work this demands. I know such a work is needed and I know I am up to the task.  So to those who tell me it cannot be done, I say, watch me do it!