What to know about Pompe disease and treatments highlighted in Trump's address to Congress

— -- President Donald Trump's first address to a joint session of Congress happened to fall on Rare Disease Day -- a fact he highlighted by recognizing one of his invited guests, Megan Crowley, a 20-year-old college student with a rare genetic disorder called Pompe disease.

After spotlighting Crowley, the president announced his intention to reduce "restraints" at the U.S. Food and Drug Administration (FDA) in order to speed up the drug approval process for diseases like Pompe.

"If we slash the restraints, not just at the FDA, but across our Government, then we will be blessed with far more miracles like Megan's," he said.

Here's a look at Pompe disease and the drugs approved to treat it through the current FDA drug approval process.

What is Pompe Disease

The disease is a rare genetic disorder where the body is unable to make an enzyme that breaks down a specific, complex sugar called glycogen. As a result, an abnormal amount of the sugar accumulates, especially affecting muscle cells. The disease affects approximately 1 in every 40,000 people in the U.S., according to the National Institutes of Health (NIH).

There are three types of Pompe disease: classic infantile-onset, non-classic infantile-onset and late-onset.

Classic infantile-onset Pompe disease begins within a few months of birth and is characterized by muscle weakness, poor muscle tone, enlarged liver and heart defects that, if untreated, will likely to lead to heart failure.

Non-classic infantile-onset Pompe disease usually appears by the time the infant is a year old and has a more subtle presentation. It is characterized by delayed motor skills and progressive muscle weakness. The heart may be abnormally large, but this defect is less likely to lead to heart failure.

The third type of the disease, called late-onset type of Pompe disease, may not show up until late childhood, adolescence or adulthood. It is generally milder, characterized by progressive muscle weakness, especially in the legs and the trunk, including the muscles that control breathing. But,the heart is much less likely to be affected.

Megan Crowley was diagnosed with Pompe disease at 15 months. Her younger brother, Patrick, was found to have the disease when he was just 3 months old.

How was the treatment developed?

During his speech, Trump used Johny Crowley's story as an example of how government "restraints" should be cut to facilitate innovation.

"Megan's story is about the unbounded power of a father's love for a daughter," Trump said. "But our slow and burdensome approval process at the Food and Drug Administration keeps too many advances, like the one that saved Megan's life, from reaching those in need."

At the time the Crowley children were diagnosed with the disease, there were few options for treatment. John Crowley decided to quit his job at Bristol-Myers Squibb in order to search for a cure and co-founded Novazyme Pharmaceuticals in Oklahoma City, with Dr. William Canfield, who was researching Pompe disease, in 1999.

The first drug to be FDA approved for Pompe disease was Myozyme, which is an enzyme replacement therapy that helps break down excess glycogen. While it can help people with the disease live far longer than they did previously, it does not "cure" it.

Myozyme was developed by biotech company Genzyme Corporation, which had acquired the company Crowley and Canfield co-founded. Crowley was in charge of managing research efforts for Pompe disease at Genzyme.

Dr. Heather A. Lau, assistant professor of neurology and director of the Lysosomal Storage Disorders at NYU Langone Medical Center, said the treatment was a "game changer" when it was approved.

"These children are now living and are living beyond the expectation," said Lau, "and they can go to school."

"They do have severe muscle weakness still and require physical therapy," and, she added, "a lot of them are unable to walk."

Before this treatment was released, said many children with the "classic" form of Pompe disease would not survive past their first birthdays.

Novazyme Pharmaceuticals began researching treatments in 1999, when Crowley co-founded the company. Genzyme Therapeutics continued the research after purchasing the company in 2001.

The drug eventually developed, Myozyme, was approved by the FDA in 2006 through their "orphan drug" program, which fast-tracks treatments for rare or especially life-threatening disorders, about nine months after Genzyme Corporation first submitted the application.

What do some health experts say about changing the drug approval process?

Part of the reason it takes months to years between the time a drug is developed and approved to be sold on the market is that it takes time to conduct trials.

Medical experts have criticized the notion of changing the current guidelines, saying those stages are necessary for safety, including World Health Organization director Dr. Margaret Chan.

"Regulatory agencies everywhere must resist the push to replace randomized clinical trials, long the gold standard for approving new drugs, with research summaries provided by pharmaceutical companies," she said during a speech last month at the University of Washington’s Department of Global Health. "As some argue, making this change would speed up regulatory approval, lower the costs to industry and get more products on the market sooner. This kind of thinking is extremely dangerous."

Drugs for rare diseases, like Pompe disease, can be designated as "orphan drugs" and fast-tracked to help patients with no other options for survival. Orphan drugs are designated for diseases where fewer than 200,000 people are affected in the U.S.

As an incentive for pharmaceutical companies to make these drugs for a relatively small population, the companies may receive tax rebates, enhanced patent protections, subsidies for research and marketing rights.

These drugs follow the same regulation process as drugs for the general population, including animal and human studies to ensure there is evidence they are effective and safe to use. However, due to the small number of people affected, the number of people required to take part in safety and efficacy studies is lower than a drug for the general population and they can be approved faster.

Dr. Michael Carome, Director of Public Citizen’s Health Research Group, a non-profit organization that champions "citizen interests," defended the current regulation process as ways to keep patients safe.

"President Trump’s claims that the U.S. Food and Drug Administration’s approval process for medical products is 'slow and burdensome' and 'keeps too many advances ... from reaching those in need,'" Carome said in a statement today, "reflect complete ignorance about the FDA’s current regulatory schemes for ensuring that medications and medical devices are safe and effective."

Dr. Darien Sutton-Ramsey contributed to this article. He is an Emergency Medicine Resident Physician and an ABC News Medical Unit contributor.