Brothers fight rare disease with a devastating impact

When sons, Jason and Justin, were diagnosed with MPS II, a rare and life-threatening genetic condition also known as Hunter syndrome, the Leider family vowed to fight. Two years later, they gave Joseph Muenzer, MD, PhD, a check for $25,000—money they raised to support his paradigm-changing research in enzyme replacement therapy, their sons' best hope.

Brothers fight rare disease with a devastating impact click to enlarge Dr. Joe Muenzer (pictured here with Jason and Justin and dad, Jeff) has spent a lifetime researching and creating the best treatment options for Hunter syndrome.


It was Jason Leider's foray into preschool shortly after his fourth birthday in 2010 that would lead to the heartbreaking news.

Something just doesn’t seem right, his teachers insisted. Jason wasn't performing age appropriately. His speech and vocabulary were less developed than his peers. His fine motor skills as demonstrated by his writing, coloring, drawing, and cutting were lagging. His social skills were a little bit "off."

"As parents we 'knew' they were onto something," recalls mom, Deena. "We saw Jason was a little different maturity wise than other kids his age and socially was not the most outgoing with children his age. He had many sensory issues, as well. When we would express our concerns friends and family would always reassure us: 'my child is or was like that, too,' 'he’ll do it when he is ready,' 'he has never been in school before.'"

But Deena and her husband, Jeff, followed their instincts and pursued the learning evaluations Jason's teachers suggested. Those led to medical visits and, later, genetic testing, which revealed something the family never expected. Jason had MPS II, a fatal disease with no cure. Worse, his younger brother, 2-year-old Justin had it, too. Their boys would be lucky to see their 15th birthdays.

MPS II, more commonly known as Hunter syndrome, is an exceedingly rare and life-threatening genetic disorder. In Hunter syndrome, the body's inability to produce specific enzymes interferes with the break down complex carbohydrates. This derails normal cellular function, where the body uses enzymes to break down and recycle cellular materials. The result is storage of these materials in the cells, blood and connective tissues, causing progressive, irreversible damage affecting physical appearance, motor ability, functioning of organs and systems, and, in most cases, mental development.

The Leiders were devastated, but when they got over the initial shock and sadness, they developed a firm resolve and vowed to fight. They soon met UNC's Joe Muenzer, MD, the nation's foremost authority on MPS, and learned Muenzer's research in enzyme replacement therapy held their son's greatest hope. In fact, it was through a clinical trial led by Dr. Muenzer that the FDA approved Elaprase (idursulfase), the first prescription medication prescribed for the treatment of Hunter syndrome. It isn't a cure but slows the neurological damage and related developmental effects. It also buys precious time.

The Leiders now travel hundreds of miles from New Jersey to UNC several times each year to see Dr. Muenzer. On their latest visit, they brought him something special: a $25,000 check to support his paradigm-changing research in enzyme replacement therapy. The family raised the money through their own fundraising efforts in their home community. They see it as much a gift for their sons as it is for other affected families.

"Our wish is to change the course of MPS II and the future of new families facing this diagnosis," says dad, Jeff.

The Leider family's gift will help Dr. Muenzer develop new therapies that will help not only Jason and Justin but other families affected by Hunter syndrome. Muenzer's current clinical trial is aimed at addressing the neurological and developmental effects of Hunter syndrome in those with the severe form of the condition through direct administration of recombinant enzyme into the fluid around the brain and spinal cord.

Learn more about Jason and Justin and their parents' fight >>

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