After numerous broken bones, osteoporosis, and multiple hip replacements, a 24-year-old graduate student in biomedical research was convinced the true cause of his skeletal issues was being overlooked by doctors. Several weeks later, he found his diagnosis—a rare genetic disease that "fit every symptom," Sandra Boodman writes for the Washington Post.

Slide deck: Musculoskeletal health trends for 2022

A lifetime full of skeletal issues

Since birth, Aaron Blocker had experienced numerous issues with his bones. He was born with severely bowed legs and had to wear metal leg braces every night to help him walk. Still, Blocker said his legs "always hurt."

When he was 10, he fractured several fingers after falling on his hand—the first in a long line of incidents resulting in broken bones. A few years later, Blocker broke his nose when a swing made of soft plastic hit his nose.

"My family just thought I was a clumsy child," Blocker recalled. "I was very active." However, his problems extended beyond broken bones.

"I had a lot of issues with my teeth growing up," he said. During his youth, his molars, would mysteriously crack. By his high school graduation, he had already had seven teeth extracted. In addition, he had numerous cavities—a symptom his dentist attributed to "weak teeth." 

In his senior year of high school, after Blocker was hospitalized for two weeks following months of abdominal pain that caused his weight to drop to 100 pounds, he was diagnosed with Crohn's disease. To treat the condition, doctors prescribed a low dose of prednisone, a corticosteroid, for eight weeks.

One year later, in January 2011, Blocker was hospitalized when the condition flared again. During his hospitalization, an abdominal CT scan revealed that he had avascular necrosis of both hips. In addition, a bone density scan detected severe osteoporosis.

"The orthopedist told me my hip bones were dying and said it could be related to the prednisone use," Blocker said. However, Blocker thought that suggestion was questionable, largely because he had only taken a low dose of the drug for about eight weeks.

Within a year, after alternative treatments had failed and Blocker's hip joints started collapsing, both hips were replaced.

From 2012 to 2016, Blocker broke his nose and wrist again, along with several toes. For years, Blocker's doctors set his broken bones and treated several other orthopedic problems, including scoliosis. However, none of his doctors ever suggested investigating a potential cause.

Then, when Blocker's hip replacements prematurely failed, he became convinced that the cause of his skeletal problems was being overlooked by his doctors.

"I knew in my gut that something was not right," he recalled. "It made no sense to me that these had failed when they're supposed to last for 15-plus years. I thought, 'I'm going to try to figure it out if nobody else will.'"

'I realized I fit every symptom'

At the time, Blocker was a 24-year-old graduate student in biomedical research. He spent several weeks combing through his medical records and searching scientific websites before he found a potential diagnosis.

As he reviewed his medical history, he noticed that his level of alkaline phosphatase (ALP), was always very low. Low levels of ALP can indicate a zinc deficiency, malnutrition, or a rare genetic disease called hypophosphatasia (HPP), which causes bone and dental issues and affects around 1 in 100,000 people.

"I realized I fit every symptom," Blocker said. "I thought, 'This could be it.'"

Blocker took his findings to his family physician, who said he had never heard of HPP. However, he referred Blocker to a geneticist at the University of Mississippi.

After the geneticist reviewed Blocker's medical history—including his bowed legs at birth, numerous fractures, osteoporosis, and history of hip replacements—he ordered genetic testing for HPP.

When the results came back, they confirmed Blocker's hypothesis. He had inherited HPP in an autosomal dominant pattern. According to Blocker, who was raised by his maternal grandparents, he still does not know which parent gave him the gene.

'How did this go missed for so long?'

"It was a relief to have an answer," Blocker acknowledged. "But I've always wondered, how did this go missed for so long?"

According to one of Blocker's doctors, he may have gone undiagnosed for so long because of the evolving scientific knowledge about HPP, as well as Blocker's complex medical history.

"I was relieved," Blocker said when he learned that something other than clumsiness or bad luck was responsible. "It was nice to be right and not feel like a crazy person and have an answer."

After Blocker was diagnosed, he soon realized he would need to travel out of state for specialized care. He went to see Kathryn Dahir, an endocrinologist at Vanderbilt University School of Medicine, who specializes in metabolic bone disorders and treats patients and families affected by HPP from "cradle to grave."

Blocker now takes Strensiq, the only drug approved to treat HPP. It is designed to replace ALP and improve bone health.

"He was very impaired with no other treatment available," Dahir said. "He's doing okay, but he continues to have additional surgeries." (Boodman, Washington Post, 7/9)