A Rare and Life-Threatening Diagnosis

William was born with Pearson syndrome, an extremely rare mitochondrial disorder. At the time his story was published in 2020, fewer than 100 children worldwide were known to have the condition.

Pearson syndrome is caused by missing genetic material in mitochondrial DNA. Because mitochondria help the body’s cells produce energy, the disease can affect many organs.

Children with the condition often develop severe anemia and pancreatic problems. It may also damage the liver, kidneys, heart, eyes, ears, and brain. The disease has no known cure and can be fatal.

Doctors initially believed William had a rare form of childhood anemia. After additional genetic testing and consultations with specialists at Boston Children’s Hospital, he was diagnosed with Pearson syndrome.

His parents, Elizabeth and Jeff Reynolds, were devastated—but determined to fight for their son.

William is one of fewer than 100 children worldwide known to have Pearson syndrome

Turning Fear Into Action

Just two months after William’s diagnosis in 2015, his parents created the Champ Foundation, a nonprofit organization dedicated to funding Pearson syndrome research.

Their efforts helped doctors and scientists collaborate, share information, and search for possible treatments for a disease that had received little research funding.

For the next two years, William remained relatively stable. His blood counts improved, and he showed few additional symptoms.

Then, in 2019, his family traveled to Israel so he could be considered for an experimental mitochondrial therapy. During the required testing, doctors discovered that William had developed myelodysplastic syndrome, or MDS—a serious bone marrow disorder sometimes described as a form of “pre-leukemia.”

The diagnosis meant he could not join the clinical trial.

William at 6 months, surrounded by letters of support

A Gift From His Little Brother

Fortunately, William’s parents had saved Teddy’s umbilical cord blood when his younger brother was born. The brothers were a genetic match, and the cord blood contained healthy stem cells that could replace William’s diseased blood-forming cells.

William received a cord blood stem cell transplant at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center. The procedure successfully treated the blood-related complications of his condition.

However, the transplant was not a complete cure. Pearson syndrome affects the entire body, so William still required careful medical monitoring and continued research into new treatments.

William’s journey became more than one family’s fight. Through the Champ Foundation, his parents helped bring researchers together and created new hope for other families facing the same rare diagnosis.

And for William, the science could be explained in the most meaningful way of all: His little brother’s cells helped give him another chance.