Editor's note: Feb. 28 is Rare Disease Day, a worldwide observance meant to raise awareness and generate change. It was with that observance in mind that Chris Ostertag offered to share his family's story.

In 2017, Chris Ostertag looked forward to the birth of his second child, imagining him sitting up, crawling and saying his first words. Ostertag and his wife, Rachel, pictured their son and his big sister chasing after each other and making mischief.

"We had a full-term pregnancy," Ostertag says. "There were no concerns."

But immediately after the birth of the son the couple named Hans at SSM Health St. Mary's Hospital in St. Louis, doctors whisked him away for testing. Among other concerns, he had a large fontanelle or "soft spot" on his head and low-placed ears. The next day, Hans didn't pass a hearing screening.

Even so, his father hoped for the best. "He seemed healthy and happy to me," says Ostertag, regional director of clinical ethics at Intermountain Health, Peaks Region in Broomfield, Colorado.

At about 6 weeks, Hans failed another hearing test, and Ostertag began to worry in earnest. When Hans was 3 months old, geneticists finally diagnosed him with Zellweger spectrum disorder. The condition falls under the category of peroxisomal biogenesis disorders in which the body doesn't produce parts of a cell vital to many biochemical processes. Only one in every 50,000 to 70,000 infants is born with Zellweger spectrum disorder.

"They told us it was a terminal condition, that there was no treatment for it," Ostertag says. "It totally rocked our world."

'Tell me what a good day looks like'
Peroxisomal biogenesis disorders are characterized by neurological deficits, loss of muscle tone, liver dysfunction, kidney abnormalities, hearing loss and vision problems. Hans would ultimately lose all hearing and sight.

But even though Hans never sat up, crawled or talked, he responded joyfully to tactile interactions such as cuddling and playing.

"He loved to be tickled, to laugh and roll around," Ostertag says, "and to hold your fingers and grab your glasses."

As he grew and aged, Hans continued to interact much like a 6- to 9-month-old, Ostertag says.

When Hans was 2, the Ostertags met with Dr. Lauren Draper, a pediatric hematologist and oncologist who was then at SSM Health Cardinal Glennon Children's Hospital. They wondered about a cochlear implant, hoping it would enhance Hans' enjoyment of music. With Draper's guidance, they decided the risks were too great.

The idea, even though they ruled it out, is emblematic of the family's focus on giving Hans the best quality of life possible, Draper says. "One of the most important questions for parents is, 'Tell me what a good day looks like for your child,'" Draper says, "because it's going to be different for everybody and it's going to be different at different points in time."

No guidebook for care
After turning 3, Hans started having more issues. He required a feeding tube, needed frequent blood transfusions due to internal bleeding, and began sleeping more after medicine to combat seizures that left him lethargic.

As the years passed, the family had many conversations with Draper about Hans' palliative care. Draper made a point of bringing up subjects before a situation became dire. For example, when Hans began having two blood transfusions a week, Draper asked the Ostertags to think about what would happen if he needed more — when would the suffering outweigh the benefits?

"It helps to illuminate where we may be headed before we get there, to give parents time to absorb the information," she says.

Draper, who is now at Akron Children's in Ohio, had had one other patient with a different peroxisomal biogenesis disorder, but she'd never encountered the even more rare Zellweger spectrum disorder.

"With a rare disease, there's no guidebook," Draper says. "It keeps you on your toes as a doctor, and really makes you humble."

An organization of parents and medical professionals called the Global Foundation for Peroxisomal Disorders served as a resource for Draper. For the Ostertags, it was a lifeline that pulled them out of isolation. Both Draper and Ostertag are now on the foundation's board.

"That community has become family — and in some ways even closer than family — because there's a shared experience that even my own parents and siblings don't quite have," Ostertag says. "And there's a shared understanding where you can talk about things without a filter and you know people get it."

Adapting and advocating
Ostertag's Catholic faith helped him navigate the difficulties of parenting a child with a rare, terminal illness. He says rare disease advocacy fits squarely within the tenets of Catholicism.

Ostertag points to the Ethical and Religious Directives for Catholic Health Care Services, which advocates for those vulnerable to discrimination, specifically mentioning "persons with mental and physical disabilities."

"So I think caring for those with rare diseases is essentially right at the heart of the mission," Ostertag says.

Hans changed the Ostertag family in innumerable ways. Before his son's diagnosis, Ostertag was finishing up the first year of his Ph.D. program in health care ethics at Saint Louis University, imagining a career in academia, perhaps teaching bioethics. But as the family spent more and more time at Cardinal Glennon, Ostertag's career aspirations shifted to hospital settings. Last summer, the family moved to Colorado for his job with Intermountain Health.

Hans had an enormous impact on his sister Sophia, not quite 2 when he was born. She spent her toddler and early school years learning to help care for a sibling with many special needs. As Sophia grew, her relationship with Hans went from bringing him toys to changing diapers and pushing his wheelchair.

"She was an amazing big sister," Ostertag says.

Beautiful memories, important lessons
In June 2023, 5-year-old Hans was hospitalized with sepsis, his organs failing. The Ostertags realized it was time to let him go, and that 7-year-old Sophia should be there. Draper helped Sophia give Hans his last bath, and make a bracelet with both their names. She arranged for an adult bed to be brought in so a family member, including Ostertag's mother-in-law, could lie with Hans and encircle him. "Physical touch, hugging him, had always brought him comfort," Draper says.

Hans died June 16, 2023. For Draper, it was important that the family experience as much beauty and meaning in Hans' death as they did in his lifetime.

"There is nothing that takes away the trauma and the pain," Draper says. "But we can alleviate some of the suffering for the family and also make a memory."

Ostertag is left with many beautiful memories of his son, and lessons from his life.

"He taught us so much about the power of presence, the ways you can express love without words, and to appreciate the little things," Ostertag says. "And also, that those little things aren't really little things — they're everything."