Brian Littrell is known as one of the members of one of the most successful boy band of all time. The Backstreet Boys have been around since the 90s, and haven't seemed to let up at all. They perform in countless concerts every year, and continue to make every 90s kid smile with their classic songs.

Even though they have been busy over the last 20 years, many of the band members have found time to have a family. Brian Littrell met model and actress Leighanne Wallace during the video shoot for "As Long As You Love Me" and they quickly fell in love. By 1999, they were engaged, and then in September 2000, they were married.

The two welcomed their son Baylee Thomas Wylee Littrell on November 26th, 2002. However, when his son turned six they found something that would connect the young boy to his dad in a surprising and unexpected way, a way no parent would want.

Brian Littrell was diagnosed with a heart murmur when he was born. It lead to several complications over his life, including an open heart surgery in 1998.

Brian's Condition

His heart murmur was incredibly dangerous. "I was born with what they call a VSD, which is a ventricular septal defect," Littrell explained. "It is known as a heart murmur. Fast forward in my life when I was five years old. I was in the hospital for two months, where I was clinically supposed to die. I had a zero percent chance of living. I had a bacterial infection called bacterial endocarditis. Again like I said a zero percent chance of living."

He managed to survive, but it wasn't the end of his troubles. "It is only by the grace of God that I am here today. We fast forward to when I was 18. I was a Backstreet Boy. I left home to pursue the entertainment world," Littrell said. "At 23 I had open heart surgery to repair my VSD. So as we talk about faith and as we talk about our journey in life being a heart patient, and being a man of faith and the church; it has always been my stronghold in life. It has always been my compass. God has walked with me every step of the way as a I am heart patient even today."

After managing to survive this traumatic event, Littrell was able to use his fame for good. He was able to found his own charity to help others suffering from similar issues called the Brian Littrell's "Healthy Heart Club" For Kids. It is  a non-profit organization that assists families who have children with heart conditions with their medical, financial, and practical help.

However, never in a million years did Littrell think that he would need to worry about his own child's heart, but unfortunately, that was the unique connection that he and his son shared...

Baylee's Mysterious Condition

They had been concerned about the potential of Littrell's condition being passed down genetically, but they didn't see anything at the start. "That was our first concern when my wife and I did sonograms and checking on our son, who now is 13 years old," Brian explained. "Life happens quickly. That was a major concern of ours. His pediatrician and doctors knew of my preexisting condition as well as being a heart patient my whole life."

However, even though it didn't present right away, Littrell knew that he had to stand up for his son. "Being a father is kind of a helpless situation. You are truly in God's hands because you can't do anything about it. You can only be an advocate for your child."

Baylee was rushed to the hospital when he was six years old, but his symptoms were confusing even the doctors. The young boy came in with a high fever, a full-body rash, swollen lymph nodes and blisters covering his entire throat.

The doctors tested for so many things including strep throat, hand, foot and mouth disease, allergies, and many others. "You feel helpless as a parent because you're relying on people who are educated about these things," Littrell said of the situation.

Leighanne, Baylee's mom, couldn't just sit by and wait. She had been watching these symptoms slowly crop up over the span of a couple months. Leighanne explained that the rash first appeared in October and her young son would occasionally complain about a sore throat, but it was never serious. "I think his body was fighting off this disease," she said.

When it escalated, it did so quickly. A high-grade fever appeared and the swelling in his throat felt like pecans under the skin. He was first diagnosed with strep throat but the tests proved that wasn't the case.

The symptoms he was presenting were not pointing to anything that made sense, but Leighanne requested a test that the doctors hadn't initially wanted to do. "I said, 'before we go, I would love an echocardiogram.'"

It was this instinct that helped save her son's life...

A Mother's Instincts

Leighanne had to demand the test because the doctors didn't suspect that his heart was the problem. She was so glad that she trusted her gut. "Listen to your instincts and hopefully you're wrong, but maybe you're right," she said.

With her husband's heart condition in mind, she requested the echocardiogram. She had looked up her son's symptoms, and while they weren't the typical presentation of the heart condition known as Kawasaki Disease, it was the only thing that fit.

Kawasaki Disease is hard to diagnose as it often presents in different ways. However, it primarily affects children under five, and usually those from Japanese or Korean parents.

But the echocardiogram revealed what Leighanne had suspected. Baylee's heart was inflamed. "We didn't know what we were dealing with until we found his coronary artery three times the size it should be," Brian Littrell said.

"Baylee was finally diagnosed with [atypical] Kawasaki Disease," said Littrell. "We would like to stress [atypical] because Baylee did not have textbook symptoms of any of the viruses they thought he had."

The heart condition was scary, but they were lucky to have found it when they did. They were able to treat the swelling, and after just a few weeks he was starting to see improvements.  "He received an IVIG, which is a treatment to bring down the inflammation in his coronary arteries," Litrell said. "Baylee will be closely monitored for the next 6-8 weeks by a Pediatric Cardiologist to see if the treatment was effective."

"Baylee's cardiologist thinks he's going to make a full recovery and be able to do whatever he wants," a family friend said after they were out of the hospital.

Years later, Baylee has moved on from the scary incident. He has actually become incredibly successful in his own right, taking after his father and heading to the stage...

Baylee's Future

Baylee may have had a rough start, but he has moved on from his hospital stays and has discovered a love of music, just like his dad.

When Baylee was only seven, he performed at his parent's vow renewal ceremony. When his dad went on tour with the Backstreet Boys and New Kids On The Block, a then nine-year-old Baylee stepped on stage and opened for his dad's popular band to a huge audience.

When he was 13, Baylee landed a role in a Broadway musical called Disaster! and he actually credits his autoimmune disease for teaching him how to be strong and brave.

"It gave me a lot more strength and courage," Baylee said. "I remember I walked out of the hospital in a Batman costume. I was like, "˜I walked out of here and I survived this and everything is going to be amazing.'"

Baylee plays twin siblings in the show, and has to switch in and out of a wig to play the sister, even singing as two characters. "It was really hard at first," he admitted. "It's just so fun and so fast-paced, going back and forth. It's the best number of the show, I love it."

He's grown up a lot since his time in the hospital, and is excited to see where his life will take him. He's even contemplating following his dad into the music business, although he'd rather do it without a band by his side. "I'd like to follow in his footsteps -- solo," Baylee joked.

His dad is proud of all the things he is doing and calls him an "old soul." But he  does have some words of advice to pass down. "It comes down to hard work. It comes down to work ethic and spending time on things that you want to be valuable in life," Littrell said. "I spend a lot with my family. I spend a lot time with my career. Those are the things that I want to continue to be successful at. Those are the things that I am teaching Baylee. He tells me that it is hard work. I say that you have to spend time. You got to put that time and effort in. He is doing well. He is like a little pro."

Obviously, his son is on the path to bigger and better things, but it's all because his parents advocated for their son's health, and realized that his condition could not be ignored. Parents know their kids better than anyone and in this case, the fact that they wouldn't give up save their son's life.