Hissing and Growling Manx

Question
Just recently my female Manx Cat age 3 years old started to take the aggressive stand with my Son (eight years old) hissing and growling showing of teeth really scared him. I could figure it out since they played so well together. My son can't figure it out either, and really loves his cat. Thereafter my cat would side next to me on the couch and as I would pet her and call her name she would start to hiss and growl a deep long sound I found to be quite menesing.I don't know if I should get rid of her cause I am afraid she might attack and bite my son or I! what should I do?? I want my old friendly cat back.

Answer
Hi Robert,  This is not normal cat behavior.  Please have the Vet do a good exam and blood work. Something is just not right.  
I mainly answer Feline health questions.
You can direct the behavior part of this question to another one of our cat experts here on the allexperts site.   

Hope it is medical and the Vet can repair this problem behavior.

Blessings to you.

Marie Peppers LPN Ma