Transcript for Dr. Oz says he missed signs of his mom’s Alzheimer’s disease
Back now with Dr. Oz who's revealed his mother has been diagnosed with Alzheimer's. He adds he feels guilty for missing the warning signs and Paula Faris has the story. The family is just heartbroken. He and his sisters noticed the mother was acting differently but didn't put the pieces together. He feels gut punched, guilty he missed those signs which could have made a huge difference in treatment. Thrilled to be back. Reporter: He's one of America's most popular doctors. But this morning Dr. Oz revealing that even with his years of medical training he completely missed the signs of his own mother's Alzheimer's. So I want to start the season with the most personal show I've ever done. Reporter: Dr. Oz saying on his show Monday that the clues of his mother's disease were there, like using the wrong words or dressing oddly but he just didn't see them. And I blame myself because I realized that if I found it earlier it could have helped delay or stall it. The clues were there. Reporter: He and his family started realizing something was wrong after his mother who was already stubborn started behaving irrationally. We all saw parts of my mom falling apart. Her makeup wasn't perfect. My sister would see that one of the sisters. She would start giving away things to people she didn't really know. Another sist saw that. Reporter: Doctors say the earlier Alzheimer's is diagnosed, the better chance treatments have of working. This picture showing his mother with one of his four children, Daphne. This is a painful picture to look at because my mom doesn't remember Daphne anymore. Gosh, they had a good time together. Reporter: Here's his mom joining him on Skype. You look beautiful, mom. I love you. Thanks for coming on. Thank you. Thank you very much. I must tell you, though, I love your show. Reporter: And now today at age 81. I wait to get pretty, more prettier. Reporter: Denial is strong when it comes to illness. Even with Alzheimer's running in his family he missed it. It's a chameleon of a disease. Amen. It's slippery. You don't want to admit it because it's too painful. I think anyone who has a parent with Alzheimer's has a bunch of conflicting emotions. One, you're upset and sad at the loss of your parent but also you're wondering if you're seeing your own future. Reporter: Now he hopes their story will help others avoid the same mistake he made. I'm going to lose my mom twice. I'm going to lose her as the woman that knows me. He says that is the toughest part, losing her twice. Her memories are starting to fade. That bright light that made her who she was is starting to dim. He's also learned, you guys, he carries the gene and wants to talk about this for the 6 million right here in the united States who are dealing with Alzheimer's and the 16 million care givers giving their heart to them every single day. Let's talk about it more with Jen Ashton. He feels guilty. Is it a surprise he missed the warning signs. No, we have an unwritten law you don't treat relatives. This is why. We cannot be objective. You can't remove your emotions and denial is incredibly powerful even when you have the training and the knowledge to be able to recognize things so very, very common what he's going through. How do you distinguish between the sips of Alzheimer's and normal aging. There's some hallmark early warning signs. Look at this list, changes in mood or personality. Decreased or poor judgment. Confusion with time and place and challenges in solving problems like making a recipe that's familiar to you. Get medical attention, be formally evaluated. He's a close personal friend of mine and I was in touch with him last night. He said the symptoms sound easy to identify but the disease is like a snake in the grass so hard to see plus any wind like his father's illness throws the family off the scent. If you catch it early there are certain treatments. Increased awareness is so Yeah. Daph just had her fourth She was a flower girl in my wedding so this is personal for us.
This transcript has been automatically generated and may not be 100% accurate.