Though it has been little studied, there is growing evidence marijuana and compounds derived from it may treat the symptoms of multiple sclerosis, epilepsy, glaucoma, diabetes, cancer, HIV, and inflammatory diseases. A study released last month showed promise in preventing Alzheimer's progression.
The drug appears to have low toxicity and little risk of physical dependence. An overdose death has never been reported.
Garrett already takes Onfi, an addictive, controlled substance. He takes Diacomit, only conditionally approved in the U.S., that costs the family thousands of dollars to get from Europe. It's not covered by their insurance.
Yet, the Branns say Gov. Corbett has been unwilling to sit down with them to discuss medical marijuana as an option for their son.
They and other families like them are campaigning for access to a strain of marijuana so low in THC, the psychoactive compound of the cannabis plant, it doesn't get kids high. The strain is high in cannabidiol, which can be extracted and consumed as an oil.
It's called Charlotte's Web and it's available only in Colorado, where so-called marijuana migrants from across the country have turned, desperate for help for their sick kids.
Corbett has publicly vowed to veto any medical marijuana bill the legislature passes. And there is a bill. Two Pennsylvania state senators working across the aisle are in final drafts of S.B. 1182, the Compassionate Use of Medical Marijuana Act. It aims to legalize forms of medical marijuana like Charlotte's Web.
It is cosponsored by Sen. Daylin Leach (D., Montgomery) and Sen. Mike Folmer (R., Lebanon), who say they have the support of other Republican and Democratic senators. A similar bill in the House is sponsored by Rep. Mark Cohen (D., Phila.).
Still, the bill faces an uphill fight. State Sen. Pat Vance (R., Cumberland), a former registered nurse who heads the senate's Public Health and Welfare committee, says there isn't enough evidence now to support a wide ranging bill, but that could change.
Leach said it all hinges on Corbett.: "The legislative leaders say they won't run this bill if the governor is just going to veto it."
Leach held a news conference last month to raise awareness of the bill. It was augmented by a rally of 50 families, including the Branns.
Corbett expressed his compassion but vowed to stand his ground. "His compassion is coupled still with his opposition to legalization of marijuana even for medicinal purposes," said spokesman Jay Pagni.
The governor has given many reasons for his opposition. His latest: Marijuana hasn't been approved by the U.S. Food and Drug Administration for medical use.
In fact, it is listed as a Schedule 1 drug by the U.S. Drug Enforcement Administration. That means it is considered highly addictive and dangerous, and shows no promise as a therapeutic drug.
Marijuana and, by association, the oil extract cannabidiol, is considered more dangerous than cocaine, meth, and morphine.
Experts say the classification has made it notoriously hard to study the drug. Few robust studies have been done with marijuana and none has been in children. Most of what is known is coming from labs in Britain and Israel, and most of those studies have been done on rodents.
"If the politicians want to spend their time on legalizing medical marijuana, their time would be better spent lobbying to have it removed from Schedule 1," said neurologist Brenda Porter, an epilepsy expert at Stanford University.
In the United States, researchers must apply for a special license through the National Institute on Drug Abuse. Porter said that can take up to a year.
If approved, they must acquire a registration number from the DEA, order the drug from its single research source at the University of Mississippi at Jackson, and adhere to strict security measures in the lab. Joseph Moses, a DEA spokesman, said the agency had granted registrations to just over 100 researchers.
Charlotte's Web is named for Charlotte Figi, a 6-year-old in Colorado who was one of the first to try the strain. It's grown by six brothers who run a dispensary there.
Like many kids with Dravet, Charlotte by age 4 had lost the ability to eat, speak, and walk. She was having up to 1,200 seizures a month. Her parents put a "do not resuscitate" order in her medical records after a particularly bad episode.
Desperate for anything, Charlotte'sher parents learned about cannabidiol's potential. They connected with the Stanley brothers, and soon, Charlotte was consuming the oil of the plant, worthless to users seeking a high.
Today, she is walking, riding a bike, speaking, and eating. She has about four seizures a month.
But legalizing medical marijuana wouldn't necessarily guarantee Pennsylvania families access to Charlotte's Web.
In New Jersey, where medical marijuana is legal, the Wilson family of Scotch Plains recently obtained a low-THC, high-cannabidiol strain produced by the Egg Harbor dispensary for their 2-year-old daughter, Vivian, who also has Dravet.
In August, Gov. Christie approved edible medical marijuana products for children like Vivian, as long as they have notes from three doctors. But the Wilsons have been left to extract the oil on their own and have yet to find a lab that will test its potency.
This month, Porter and a colleague published a survey of parents who had opted to give their severely epileptic children cannabidiol-enriched cannabis.
Of the 19 children included, 84 percent reported a reduction in seizure frequency. The average number of drugs they had tried before cannabidiol was 12. On cannabidiol, more than 60 percent of children came off of their other drugs.
"It's easy to understand why people might be desperate if nothing else they've tried seems to be working and they are running out of options," said Stephen Falchek, chief of neurology at Nemours/Alfred I. duPont Hospital for Children in Wilmington.
He stressed that without more reliable studies, pediatricians were hard-pressed to recommend it.
But there is hope. Last month, a British firm, GW Pharmaceuticals, announced its drug Epidiolex had been granted orphan-drug status by the FDA.
Two researchers, one at New York University and the other at the University of California-San Francisco, will conduct clinical trials of the drug on 125 kids with Dravet and other seizure disorders who have stopped responding to traditional medicines.
"There is reason to be hopeful and to push for greater studies and trials," said Falchek.
The Branns say they don't have time to wait for the scientists and bureaucrats to figure it out. They want Garrett to have access to medical marijuana now. They would enroll him in clinical trials.
Garrett is in Colorado this month with Christine, while his father stays behind with his 7-year-old sister. He has appointments with two doctors there who have worked with other Dravet kids and who could eventually prescribe him Charlotte's Web.
"We can't sit here and wait for the scientific evidence to exist," said Garrett's father, Eric. "I don't see any downside from the stuff we're already giving him now."
But to start, Christine said she'd really just like to talk to Corbett. "When you take away the stigma and the politics, it only makes sense that this be available to the people of Pennsylvania."