Sanfilippo syndrome, also known as mucopolysaccharidosis type III, is a rare life-threatening disorder that interferes with metabolism. While it doesn’t have a cure, some symptoms can be treated to manage this condition. Here’s everything you need to know.
What Is Sanfilippo Syndrome?
Sanfilippo syndrome is a genetic disorder that affects your child’s metabolism and brain development. A person with this condition lacks a key enzyme that breaks down a type of waste produced by the body.
Enzymes are proteins that help you break down or metabolize various substances including food materials such as sugar. Within your cells, they are located in sacs called lysosomes. These lysosomes are affected by Sanfilippo syndrome, which is why this disorder is regarded as a lysosomal storage disease.
Specifically, Sanfilippo makes the body unable to break down a molecule called heparan sulfate — a natural cellular substance usually metabolized and recycled through enzyme action. As a result, heparan sulfate starts to build up in the cells and stops them from functioning correctly. This eventually leads to organ damage, growth disorders, behavioral problems, and severe neurological deterioration over time.
Sanfilippo syndrome is seen in 1 in 70,000 births in the U.S., and children with it have a life expectancy of 10 to 20 years, on average. While it’s considered a rare disease, having a family history of it increases the risk for your child.
Types of Sanfilippo Syndrome
Normally, four enzymes break down heparan sulfate, so Sanfilippo syndrome has four types based on the missing enzyme type. Some types are less aggressive than others, and life expectancy varies, too. Of course, each child is unique and lifespan estimates vary based on different factors.
Sanfilippo syndrome type A
This type is the most common and also the most severe. Children with this type will usually lose their ability to walk and talk early. Type A progresses rapidly, so advanced Sanfilippo syndrome symptoms appear at an earlier age. Children with type A have the shortest life expectancy — 15 years on average — of all four types of the syndrome.
Sanfilippo syndrome type B
This type is less common and usually progresses more slowly than type A. Research shows that children with type B have an average lifespan of about 19 years.
Sanfilippo syndrome types C and D
These two are the least common kinds of Sanfilippo syndrome, with type D being the rarest of all four types. They generally progress more slowly than types A and B.
Children with types C or D may hold onto some motor skills, such as walking and talking, longer than those with the other types. Children with type C may live to about 23 years of age. Type D is so rare that there is too little evidence to predict an average lifespan.
Sanfilippo Syndrome Symptoms
Early symptoms often appear from birth to age 2, but sometimes parents don’t notice the symptoms or doctors confuse them for other conditions.
Early Sanfilippo syndrome symptoms include:
- Breathing problems during the first week of life
- Coarse facial features (foreheads and eyebrows that stick out and full lips and nose)
- Lots of body hair (a condition called hirsutism)
- An unusually large head (macrocephaly)
- Upper respiratory congestion that doesn’t go away
- Diarrhea or loose stools that don’t go away
- Umbilical or inguinal hernia (part of your insides, like a loop of intestines, bulge through a weak spot in the lower abdomen or belly button)
- Behavioral issues similar to autism
- Speech and development delays
- Frequent ear or sinus infections
- Trouble sleeping (difficulty falling and staying asleep)
- Compulsive behavior, hyperactivity, and poor sense of safety
Symptoms worsen as the disorder progresses. Children with Sanfilippo syndrome lose their ability to walk, talk, eat, and hear over time. Sleep and behavioral issues also worsen.
Late symptoms of Sanfilippo syndrome include:
- More pronounced facial features
- Decline of learning, thinking, and self-care abilities
- Autism features such as trouble interacting with others and repetitive speech/behaviors
- Shrinking brain tissue (brain atrophy)
- Seizures
- Movement problems and stiff joints that progress to the inability to walk
- Behavior problems, including more intense hyperactivity and impulsivity
- Chewing and swallowing problems
- Hearing and vision loss
- Bigger than normal liver or spleen
- Early death
Sanfilippo syndrome eyebrows
Parents might notice that their child with Sanfilippo syndrome looks different than their siblings. Large eyebrows with more hair than expected are a unique feature of this condition. These facial features become more pronounced as children with Sanfilippo syndrome age. Their eyebrows thicken and may even grow across their forehead into a single brow.
Sanfilippo Syndrome Stages
All types of Sanfilippo syndrome progress through three phases. The timing of each phase varies, and symptoms may overlap from one phase into the next. The rate of progression through the phases can be rapid for some and slow for others.
In very rare cases, your child might not have any obvious symptoms of the disorder during childhood and doesn't progress through the stages until they are a teenager or adult. Doctors call this an “attenuated” form of the syndrome.
Phase I takes place between the ages of 1 and 3 years when early symptoms appear. You may notice your child’s speech and cognitive (learning and thinking) development slows down.
Phase II begins around the ages of 3-4 years. Behavioral and sleep challenges worsen during this phase. Hyperactivity, impulsivity, anxiety, and autism-like behaviors may become extreme during this phase. Learning and thinking abilities decline, too.
Phase III typically starts in the teen years with the onset of dementia-like symptoms that progress to a vegetative state — your child is awake but unaware and unable to interact with their surroundings. Children in this phase lose their ability to move, communicate, and eat.
Sanfilippo Syndrome Diagnosis
Most doctors don’t test for Sanfilippo syndrome during its early stages, as it’s a rare disease with symptoms that are easily confused for other conditions such as autism or ADH. But early diagnosis is important to access clinical trials and get the best support and services for your child.
If your child has a combination of developmental delays, birth defects, and other early symptoms, their doctor may suggest genetic or metabolic testing.
But the first screening test for Sanfilippo syndrome is usually a urine test called the Urine MPS Screening Analysis. If there are high levels of heparan sulfate in your child’s pee, it may mean they have Sanfilippo syndrome.
Doctors confirm a Sanfilippo syndrome diagnosis with a blood test that checks enzyme activity. Your doctor may recommend this blood test if getting a urine sample from your child is difficult or not possible.
Sanfilippo Syndrome Treatment
There's no cure for Sanfilippo syndrome. Instead, doctors focus on providing supportive care — care that eases symptoms and helps a child with Sanfilippo have the best possible quality of life for as long as possible.
Clinical trials explore different experimental medications and treatments such as enzyme replacement therapy (ERT) and gene therapy. While these options aren’t FDA-approved, you may find that taking part in a clinical trial is the best option for your child. Other options include:
Speech-language therapy
Speech delay is a common early Sanfilippo symptom. A speech-language therapist will work with you and your child to improve and maintain verbal and nonverbal communication. This includes using tools such as picture cards or electronic tablet apps that work with touch or eye gaze.
Feeding therapy
Chewing and swallowing become more difficult as Sanfilippo syndrome progresses. Because of this, many children have trouble eating safely. A speech therapist who specializes in feeding therapy will observe how your child eats. They may recommend a swallow study (a special X-ray) if your child has choking episodes. The feeding therapist will come up with a plan to support your child’s ability to eat and drink by mouth for as long as possible.
Physical therapy
Children with Sanfilippo syndrome lose their ability to move and walk. A physical therapist can help your child maintain their strength and ability to move for as long as possible by working on things like balance, flexibility, walking skills, and sitting positions.
As your child becomes less mobile, they may need medical equipment to help them get around, such as a wheelchair or specialized stroller. A physical therapist can help you access that equipment.
Occupational therapy
Orthopedic problems, such as stiff joints, are a common later symptom of this condition. An occupational therapist can help your child maintain fine motor skills they need for feeding, dressing, coloring, and playing with toys. They may also suggest activities and strategies to meet your child’s sensory needs.
Sanfilippo Syndrome Prevention
Sanfilippo syndrome can’t be prevented, but you can try to minimize risks by checking your family history. Your child is at risk of getting Sanfilippo syndrome if both you and your partner carry the affected gene. People who are planning to get pregnant can get tested to see if they are a carrier for Sanfilippo syndrome first. There are several tests available to order through companies online or through your doctor.
Another good way of minimizing Sanfilippo syndrome risk as much as possible is to check if your newborn screening has a relevant test for it.
What Should I Do if My Child Is Diagnosed With Sanfilippo Syndrome?
You might feel overwhelmed when your child is first diagnosed with Sanfilippo syndrome.
Connect with organizations such as Cure Sanfilippo Foundation, which is a great place to find information, experts, resources, and other parents of children with this rare condition.
Learn about resources and take steps to support your child’s unique needs. This may include:
- Finding and applying for clinical trials
- Creating a care team of specialized health care providers and therapists
- Applying for state or county disability services, including Medicaid and Social Security Income
- Exploring special education options
- Talking to your family about the genetic change that causes this condition
Your insurance carrier or health care system may have a care coordinator or case manager — often a nurse — to help meet your child’s needs, especially as they become more complex over time. They can help with accessing therapies, medical supplies, and other resources for support.
Caretaking for a Child With Sanfilippo Syndrome
Children with rare conditions such as Sanfilippo syndrome have many unique needs. Here are some ways to support different areas of your child’s life:
- Medical. Because this condition is so rare, many pediatricians aren’t familiar with it. Share informative Sanfilippo resources with your child’s pediatrician.
- Education. Organizations such as Cure Sanfilippo Foundation have resources to help teachers understand the condition and learn how to best support students with the syndrome in school settings. Share these resources with your child’s special education team.
- Therapies. Advocate for therapies, both inside and outside the school setting, to meet your child’s needs, which may change over time.
- Financial assistance. State and federal programs may offer financial support to cover your child’s health care costs. Nonprofit organizations may also offer funding for families with children who have rare diseases.
Nutritional support
There’s no single diet that doctors recommend for children with Sanfilippo syndrome. A dietitian can help make sure your child is getting enough calories by eating the right foods. When chewing and swallowing make eating dangerous or impossible, talk with your doctor and dietitian about feeding tube placement — a tube connected directly to the stomach for liquid food. This option depends on many different factors, and it may or may not be the best choice for your child.
For Caretakers
Caring for your child’s unique — and sometimes complicated — needs is a big job. And it’s normal to feel overwhelmed, stressed, or burnt out.
To help manage your mental load, carve out time to take care of yourself. Sometimes, this may seem impossible, but having trusted support people in place can make it easier to ask for help when you need it.
Connect with others in the Sanfilippo community. Learn from and share with others who are dealing with similar challenges. Support from your network may help you deal with challenges during especially difficult times.
It's important to talk to your doctor about overwhelming feelings of anxiety, depression, or grief. Mental health counselors or therapists can help you manage challenging feelings.
Takeaways
Sanfilippo syndrome is a rare genetic disorder that causes brain damage because the body can’t break down certain sugars. Symptoms usually start in early childhood, with developmental and speech delays, behavior issues, and loss of skills such as walking and talking. There is no cure, but early diagnosis can help you manage your child's symptoms. Connect with support groups and specialists who can help you create a health care team to meet your child’s needs.
Sanfilippo Syndrome FAQs
What is the lifespan of someone with Sanfilippo syndrome?
It depends on the type of Sanfilippo syndrome. Type A has the shortest life expectancy, about 15 years, while the lifespan of someone with type B or C may range from 19 to 23 years.
What are the first signs of Sanfilippo syndrome?
The first signs include speech and developmental delays, coarse facial features (including a prominent forehead and eyebrows, and full nose and lips), an unusually large head, and behavioral issues similar to autism and ADHD.
What is the oldest someone has lived with Sanfilippo?
Attenuated Sanfilippo syndrome is a very rare, slowly progressing form of the condition. Some reports suggest that people with this form of the syndrome may live to their 40s, 50s, or 60s.
What are the final stages of Sanfilippo syndrome?
The final stage of Sanfilippo syndrome involves dementia-like symptoms, including loss of movement, communication, and the ability to eat. These complications may lead to early death.
Do kids with Sanfilippo talk?
Yes. While speech delays are common, children with Sanfilippo syndrome can talk. As the disorder progresses, they lose their ability to talk.