'My Six Year Old Has Dementia': Mom Shares Daughter's Heartbreaking Story

She loves playing with dolls, and she really likes wearing hats. She is very clever, observant, and hilarious, and nothing can get her down for too long. She could play all day, but instead, she has to spend much of her time in the hospital, fighting for her life.

At just 3 months old, after suffering severe birth complications, Sadie Rae Haywood was diagnosed with Sanfilippo syndrome, a rare, rapidly degenerative, cognitive disease that affects a child's growth and mental development, stripping them of their ability to talk or walk or even breathe.

What Is Sanfilippo Syndrome?

Mucopolysaccharidosis type III (MPS III), also known as Sanfilippo syndrome, is a neurodegenerative disease in which the body is missing, or does not have enough of, certain enzymes needed to break down long chains of sugar molecules.

These chains of sugar molecules are called glycosaminoglycans (formerly called mucopolysaccharides), and as a result of the enzymes missing, the molecules build up in different parts of the body, causing various health problems.

Because of its neurodegenerative nature and multi-system impact, this disease is often referred to as "childhood Alzheimer's" or "childhood dementia." It causes children to lose the skills they've gained, suffer seizures and movement disorders, experience pain and suffering, and then die—often before the second decade of life.

Cara O'Neill, the chief science officer of Cure Sanfilippo Foundation, a non-profit organization that works to advance treatment options for children with Sanfilippo, told Newsweek that this fatal genetic condition, which occurs in about 1 in 70,000 births, affects the child's brain as well as their body. It comes in a spectrum of severity.

Based on that incidence rate, O'Neill said that there are likely more than 15,000 people affected worldwide. According to the Genetic and Rare Disease Information Center, there are fewer than 5,000 cases of Sanfilippo syndrome in the United States.

"In the classic and most common form of Sanfilippo, life expectancy is on average 15 years," said O'Neill, adding that autism commonly occurs along with Sanfilippo syndrome.

Four subtypes of Sanfilippo have been identified, usually referred to as MPS IIIA, MPS IIIB, MPS IIIC, and MPS IIID—or Sanfilippo A, Sanfilippo B, Sanfilippo C and Sanfilippo D, and each subtype corresponds to a particular enzyme that is missing or not working properly in the body's process of breaking down heparan sulfate.

Type A is the most common subtype, and it's also considered to be the most severe. The most common age for symptoms of this disease to show in children, also called the age of onset, is between 2 and 11 years.

Symptoms of Sanfilippo Syndrome

The symptoms of Sanfilippo syndrome can vary significantly depending on the subtype of the disease. Children affected by this condition typically do not display any symptoms at the time of birth, according to Boston's Children's Hospital. Features of MPS IIIA typically appear earlier in life and progress more rapidly than symptoms in other Sanfilippo syndrome subtypes.

O'Neill said that some typical symptoms of Sanfilippo syndrome include large head size and belly size, developmental delay (particularly speech), behavior challenges, recurrent ear infections, prominent eyebrows, and hearing loss, among others.

Other symptoms, according to the Children's Hospital, may also include arthritis, visual impairment, enlargement of the liver and spleen (hepatosplenomegaly), frequent respiratory infections, and chronic diarrhea.

Sadie's Diagnosis

Sadie's mom, Ashley Haywood, told Newsweek that after suffering breathing difficulties during birth, Sadie was immediately airlifted to a hospital in Charlotte, North Carolina, where she was put on a ventilator. She only got tested for Sanfilippo because her parents insisted.

"She also developed hydrocephalus and had to get a shunt implanted in her brain. We knew a distant relative had Sanfilippo syndrome so we had Sadie tested just to rule this out but sadly the test came back positive," Haywood said. "Sadie's story is unusual. Most children with Sanfilippo are not diagnosed until they are a few years old. Many doctors have never heard of this disease. We had to push to get Sadie tested at 3 months old."

Sadie's family was devastated after the doctors told them she had Sanfilippo but was given hope because a promising gene therapy trial was just starting at the same time. But Sadie was rejected from this trial and a few others because of her other conditions.

"They don't want trial participants to have other conditions that could confuse the trial results, which we understand but it was hard to accept," Haywood said. "We knew that in rare conditions like Sanfilippo, it's important to share your story and fundraise because many have never heard of the condition and research is often funded by families.

"Rare diseases are not as profitable for pharma companies so family support is key. We started sharing Sadie's story on social media and with media outlets and we hosted numerous fundraisers to support the Cure Sanfilippo Foundation.

"We've also been able to treasure each moment perhaps more than the average family because we know what the outcome is. We know time is limited and we want to make the most of it. We try to make as many memories as possible to make Sadie happy because one day it's all we'll have."

Sadie is still doing well because of the clinical trial she was in, her mom said. She's 6 1/2 years old now, but her cognitive age is around 3. She still talks a lot, but she's getting her words more and more confused, and while her mobility is still seemingly good, it is also degenerating, as she has started having trouble on the stairs.

She is a strong little fighter. Her parents never knew if she would talk or walk, and her cognitive abilities turned out to be surprising: "She could say all the ABCs and count to 10 before she was 2. Even if she's spending all day in a hospital bed, she's pretty happy," Haywood said.

Sadie was finally accepted into a clinical trial at age 3, where she got weekly infusions of the enzyme she's missing for two years, and the results showed that Sadie improved while on the treatment.

"We've never heard of another drug for Sanfilippo halting the progression of the disease so this is a big deal," Haywood said. "Sadly, the pharmaceutical company decided to sell the drug before the trial ended and they had any data. They brought in new leadership who wanted to focus on less rare diseases."

The Haywood family has since reached out to many other companies to share Sadie's success and ask them to buy the treatment, but according to Sadie's mom, no company did because it is very expensive and difficult to produce.

"It's very frustrating to know that there is a treatment out there that helps but we can't get access to it," she said. "We are focusing our efforts now on other trials that are coming up and doing whatever we can to help them.

"There is no guarantee that Sadie will get into them but it is our only hope. And they would need to start very quickly or this disease will cause too much damage for any treatment to help Sadie."

Causes of Sanfilippo Syndrome

Sanfilippo Syndrome is inherited in an autosomal recessive pattern, which means that if both parents carry a nonworking copy of a gene related to this condition, each of their children has a 25 percent chance of developing the disease.

There is currently no FDA-approved treatment or cure for Sanfilippo, but according to O'Neill, there is research happening and there is hope.

"At this time, clinical trials are the children's only opportunity for a potential improved outcome," O'Neill said. "Children with Sanfilippo syndrome need a proactive healthcare team which includes physical, occupational, behavioral and speech therapies to help maintain their skills for as long as possible."

Sanfilippo Treatments

Since there's no other option available for them, Sadie's family has partnered up with other Sanfilippo families to support the Cure Sanfilippo Foundation.

Cure Sanfilippo Foundation is urgently seeking funding for a "Type A Gene Therapy" clinical trial at the University of North Carolina at Chapel Hill, which is estimated to take place in 2023. Their goal is to raise $1 million to go toward research and treatments.

O'Neill pointed out that families are not personally charged for participation in clinical trials as these costs are covered by the sponsoring organization.

She added: "There is no guarantee any specific child will be enrolled in a clinical trial. Children are enrolled in clinical trials based on inclusion criteria at the discretion of the primary physician investigator."