Six-year-old twins Lucas and Parker Talbert are both struggling.
Lucas has the technical skills and learned to kick and punch in karate classes near Talbert's home in Old Fort, North Carolina.
Parker fights the wheelchair, which he can not accept. He fights his parents when he gets tired, and he fights a devastating illness.
As Lucas develops mentally and physically, the progress of his twin brother slows down.
Parker soon begins to retire. He suffers from Sanfilippo syndrome, a rare genetic disorder often referred to as "Alzheimer's disease".
A genetic disorder in children with Sanfilippo leaves little or no enzyme that can break down the body and eliminate cellular debris.
Without this enzyme, cell wastes form and become toxic – especially in the brain.
The disease robs most children of what they have learned in life up to the age of 10 years. They take back their memories, their ability to walk, speak or crawl.
Despite the family's attempts to conduct clinical trials, his family has to observe how the horizon of a twin widens – as Parker slowly moves away from them.
Jeremy and Christina Talbert's son Parker (second from left) has Sanfilippo syndrome – often referred to as childhood Alzheimer's disease – but his twin brother Lucas (right) does not suffer from it
Parker and Lucas were born too early, so they had to visit the hospital regularly to make sure they were doing well in their first year.
Hospitals, such as Christina and Jeremy Talbert soon discovered, would become a fixture in their family's life.
Lucas was fine, but one of the nurses who routinely cared for the boys worried about Parker. He did not quite keep up with his twin brother.
He appeared to hesitate in development, but Parker's physique seemed too fast to grow.
His spleen enlarged, his liver enlarged and his head was unusually large. It was enough for doctors to do more tests.
Before the family was given the diagnosis formally, a nurse told them what the results of the genetic test testified: Sanfilippo syndrome.
"She said I should not look it up before I talk to the doctor," Christina recalls. When Christina and Jeremy saw the expression on the nurse's face, they could not help themselves.
The twins were born too early in September 2012. When they were toddlers, it became clear Parker was behind Lucas
They flooded pages and pages with search results online.
When it comes to Sanfilippo, there is so much information, few answers, but too many heartbreaking facts, statistics and stories.
Government information posts and nonprofit websites are scattered with obscure terminology: "missense mutations" to genes with names that look like alphabet soup, mucopolysaccharidosis type III, neurodegenerative.
The Talberts, however, knew that their son had a devastating illness that could not be cured. Only a year and a half after his birth, they realized that Parker was dying.
"It was a time of crazy turmoil. It was horrible to read and we did not want to believe it, "says Christina.
"We prayed that [the nurse] was wrong. & # 39;
But within a few days they were back at the doctor's office and their fears were confirmed.
As a baby, Parker's cognitive development was slow, but the spleen, liver, and head all seemed to grow too fast
The news was tempered with a ray of hope. A clinical trial to treat Sanfilippo syndrome was conducted at the University of North Carolina at Chapel Hill (UNC), just three hours' drive from Talbert's home in Old Fort, North Carolina.
Christina and Jeremy did not waste time registering Parker for the 2015 trial.
The experimental treatment used a compound to degrade heparan sulfate, the toxic cells weretes the brain deposits of children with SF.
Parker's genetic mutation means that his body does not produce enough of the enzyme that removes this cell-killing waste.
The experimental drug would replace the missing enzyme – for half of the study participants who received the drug. The remainder would receive a placebo and serve as a control group.
Over the next year, Parker received three cans at UNC. Jeremy and Christina met the parents of other children in the trial, all buzzing with a touch of cautious hope.
"We met these other parents whose children were treated and thought it would help," says Jeremy.
But for Parker, "it was a false hope," he says.
Parker had been randomized into the control group, so any suggestion of improvement the Talberts believed was an illusion.
After a year in the dark, pharmaceutical company Shire allowed participants in the control group study to receive real doses of the drug.
The Make-a-Wish Foundation sent the Talberts, including Jeremy's children from a previous marriage, Carson and Ryan (left) to Disney World, where Parker was thrilled to see Mickey
Parker can only say about 30 words, but there's no doubt about his Disney enthusiasm. He wears his Mickey ears around the house (left) and he and Christina went to Halloween as Halloween and Mickey and Minnie Mouse (right).
Parker got his first dose of enzyme replacement.
"When it was finally time, it was such a relief to find that our child would be treated," says Jeremy.
"In our eyes, we really believed that it worked. He looked us in the eye, he tried to say a few words … I do not know if it was just him or we just thought it was the drug [making him better], '
However, in September 2016, the process was canceled.
"Shire said the drug did not reach the endpoints as expected, but a lot of it comes down to the money."
The drug was found to be safe, but did not prevent the loss of memory as expected. It is unclear whether funding played an important role in the company's decision to close the trial.
Sanfilippo slows the development of a child for some time, then stops the development, then the children begin to decline and lose their skills and abilities.
"Parker is learning right now He does not really learn anything else, he has a vocabulary of about 30 words, maybe five sign-language moves, and he does not try to count as usual or to color or assemble blocks," says Christina.
He can still go to school and divides his time in the preschool garden between two classes. In one, all children suffer from developmental delays, many of which are immobile. On the other hand, children are not quite that far from their development milestones.
"Being with other kids who are talking and being a bit more social helps Parker mock them," explains his mother.
Parker and Lucas (left) are very similar fraternal twins, but Parker has the "grosser" features typical of children with Sanfilippo. He can be spirited, but on good days he loves to be held in the air by his father Jeremy (right).
Despite their similarities, the Talberts say, Lucas sees Parker more as a baby than as his twin. He loves and helps the family with Parker, but he can not quite understand what's going on with his brother, and sometimes he gets frustrated with him.
The Talberts need to find a delicate balance between the sacrifices to help a twin without this happening at the expense of the other.
"Everything's kind of bittersweet," says Jeremy.
"Anything you are excited and proud to see Lucas, you have to be sad and emotional because you know Parker will never make it.
"It's as if every win comes with a defeat."
At the moment, Lucas is largely shielded from the reality of what happens to his brother. If he is old enough to understand a more comprehensive explanation – the Talberts estimate around 10 – Parker will probably only be mobile with a wheelchair.
The Talberts have recently bought Parker's first chair, but Christina says he refuses to use it.
On the Make-a-Wish Foundation trip to Disney World two years ago, Christina, Jeremy, or one of Jeremy's older children from a previous marriage, Ryan and Carson, had to carry Parker or push in a stroller.
Christina and Jeremy have recently bought a wheelchair for Parker, who refuses to use it. When he and Lucas are ten years old and his twin understands what's going on with his brother, Parker will probably have no choice but to use the wheelchair
Still, it was a great time for the family – and especially for Parker.
"Parker loves Mickey Mouse, anything that will make Mickey jump and roar this boy," says Christina.
On good days, like the one on the trip, it's almost as if you were getting something more from him. He'll look you in the eye or kiss and hug you when you're really tall, "says Jeremy.
The Talberts fear that these days will be rarer, that Parker could lose words like "please", "more" and "slide".
They're trying to find another lawsuit against Parker, but his inclusion in the Shire trial precludes him from doing so. For others, he was out of a court case also Long.
Nevertheless, the Talberts continue to raise money for the Sanfilippo research for the twins' sixth birthday last year and try to see the best in their devastating situation.
"There are so many more children with this disease than there are rooms available. They do not try to get angry or bitter and hope that if your child can not be healed, it can help a child heal this terrible disease, "says Jeremy.