Eighteen-year-old Yuji is eager to talk about his life so far with Klinefelter syndrome, as well as the choices that are ahead for him because he was born with an extra copy of the X chromosome.

“Hearing about it from someone else, it sounds bad, even sad. But when you hear it from the person who has it, it sounds OK,” the recent high school graduate says of the syndrome that affects fertility, energy levels, and bone and muscle strength in one of every 550 boys and men. 

“If you ask me, I think it’s pretty cool to be born with an extra chromosome,” says Yuji, who credits his care team at Children’s Hospital of Philadelphia (CHOP), led by Maria Vogiatzi, MD, for helping him and his parents not only understand the syndrome, but how to navigate living his best life, day by day. An attending physician in the Division of Endocrinology who leads the Adrenal and Puberty Center and the Klinefelter and Other X and Y Chromosome Variations Program, Dr. Vogiatzi has been caring for Yuji for the last four years and prescribed his current testosterone replacement therapy or TRT, the most common treatment for KS. 

Klinefelter syndrome is diagnosed by a genetic blood test that identifies the karyotype, meaning the number, size and shape of the chromosomes. A spectrum condition, not all patients experience the same symptoms, and levels of severity varies.

“I know we’re different, but we’re not all that different,” says Yuji, an accomplished tennis player who plays the saxophone and clarinet and works part-time lifting palates at a Lancaster County produce warehouse, close to where he lives. “I am a positive person. There are not many things that could really get me down.” 

Most days, Yuji says, “I feel great.” Other than when he’s administering the two pumps of testosterone gel he rubs on his stomach before bed every night to keep him strong and offset any symptoms of Klinefelter’s, he says, “It’s easy for me to forget I even have it.”

Facing the unknown

Because they were married later in life, Yuji’s parents, Keiko and Thomas, made a precautionary decision for Keiko to undergo amniocentesis during her pregnancy.

“My wife was several months pregnant, and we just wanted to check and see,” recalls Thomas. “We were stunned when they came back with the diagnosis. We had never heard of Klinefelter syndrome. … We did some research, and we learned at that time what it is.”

Thomas said it was reassuring for them to learn that Yuji had every chance to live a normal life, and that is how they raised him.

“We were going to treat him like a normal kid, encourage him and not make a big issue out of it,” recalls Thomas. “We did not look at it like an affliction, and he thrived. In all respects, he’s been normal and healthy.”

Treatment begins at puberty

Growing up, Yuji hit all the normal childhood milestones, says his father. About the time Yuji hit puberty, his pediatrician recommended that Yuji find a specialist at CHOP, “just to get him on the radar,” recalls Thomas.

Yuji was in middle school when he had his first appointment at CHOP. He underwent a battery of tests, including bloodwork for things like bone density, which he continues to do annually to ensure the testosterone replacement therapy is on track.

More than that actual first consultation, Yuji remembers the car ride home to CHOP when his dad told him he had Klinefelter syndrome — a reality his parents had shielded from him.

“I did not really know until my dad explained it to me,” Yuji remembers. “I was like, ‘Oh, that’s cool.’”

Overcoming symptoms

Looking back, Yuji says, “I always felt weaker than most people. Even my younger sisters.” His arms strength was especially low, and he was not about to challenge anyone to arm wrestling, he says with his trademark humor.

There were times, too, when he had to work harder to understand his lessons at school. He didn’t know he had a condition that could affect his memory and ability to learn.

Both decreased muscle strength and challenges with word-based learning are common Klinefelter syndrome symptoms. Whatever the challenge, Yuji says he always found a way to compensate, and move on.

“My parents didn’t want to list Klinefelter syndrome as a thing that affected me because they didn’t want people to treat me differently, which I am glad they did,” says Yuji. “They didn't even tell my family.”

Future fatherhood through adoption

While many with Klinefelter syndrome go undiagnosed for years into adulthood, Yuji is glad he found out when he did. He knows that if he takes the testosterone supplement, he will be infertile. He is not at all fazed by it.

“I was planning to adopt anyway,” Yuji says without hesitation. “It just worked out for me. But for people with Klinefelter syndrome who want to try to have children, there are ways.”  

Meanwhile, Yuji continues his annual checkups at CHOP. By the time of his next appointment in November, he will have settled into college life at Eastern Mennonite University.

He wants to be a psychiatrist. With all the necessary medical training, Yuji figures he will be 30 before he would even think about starting a family. “At that point, I will have enough money to support a family, to adopt a kid, or two,” says Yuji. “Making a home for children who need one is something I know I want to do.”