Infantile spasms-broad thumbs syndrome is a rare genetic condition that usually becomes noticeable in infancy. It often involves infantile spasms, delays in development, and broad thumbs or broad big toes. For some, the first sign may be a small change they brush off at first, but in this condition the seizures often need urgent medical attention. Infantile spasms-broad thumbs syndrome is typically lifelong, and outcomes can vary widely depending on how severe the seizures and developmental problems are. Treatment usually focuses on controlling the spasms and supporting development, and while some affected infants can become seriously ill, the risk to life varies from child to child.
How many people live with Infantile spasms-broad thumbs syndrome?
No reliable count is available for how many people live with infantile spasms-broad thumbs syndrome worldwide or in the United States. This condition is considered extremely rare, with only a small number of cases described in the medical literature, so experts do not have a firm global or U.S. estimate.
Overview
Infantile spasms-broad thumbs syndromeSymptoms
Infantile spasms-broad thumbs syndrome usually involves early seizure-like jerks in infancy, often in clusters. Many living with Infantile spasms-broad thumbs syndrome also have unusually broad thumbs or big toes, developmental delay, and sometimes feeding or muscle tone problems.
Outlook and prognosis
In Infantile spasms-broad thumbs syndrome, outlook often depends on how early spasms are controlled and how much development is affected. Many children have lasting learning and movement challenges, while seizures may improve with treatment.
Causes and risk factors
Infantile spasms-broad thumbs syndrome is usually caused by a change in a gene involved in early development, often arising for the first time in the child. In some families, it can be inherited. There are no known lifestyle or environmental causes.
Genetic influences
Genetics are very important in Infantile spasms-broad thumbs syndrome, because it is usually caused by a disease-causing gene change. In many families, this change happens for the first time in the child, rather than being inherited.
Diagnosis
Diagnosis of Infantile spasms-broad thumbs syndrome usually starts with clinical features, including infantile spasms and broad thumbs. Doctors often confirm the genetic diagnosis of Infantile spasms-broad thumbs syndrome with genetic tests. Brain imaging and EEG can also support diagnosis.
Treatment and drugs
Treatment for Infantile spasms-broad thumbs syndrome usually centers on quickly controlling spasms with medicines such as ACTH, steroids, or sometimes vigabatrin. Many children also need early developmental therapies and regular follow-up with neurology, genetics, and rehabilitation teams.
Symptoms
Early in life, families may notice clusters of brief seizures and slower-than-expected development rather than one single obvious problem. In Infantile spasms-broad thumbs syndrome, the most often reported signs are infantile spasms, developmental delay, and unusually broad thumbs, sometimes along with broad big toes. The early features of Infantile spasms-broad thumbs syndrome can affect feeding, movement, and later learning. Features vary from person to person and can change over time.
These seizures are brief but often come in clusters, with sudden bending, stiffening, or jerking of the body. They usually begin in the first year of life and may be easier to notice around waking or falling asleep.
Babies and children may be slower to gain skills such as rolling, sitting, babbling, or walking. Some may also lose skills they had started to develop after the spasms begin.
Broad thumbs are one of the hallmark signs of Infantile spasms-broad thumbs syndrome. They are present from birth and usually do not hurt, but they can help doctors recognize the condition.
Some children also have unusually broad big toes. This may not cause major day-to-day problems on its own, but it can be another helpful physical clue.
How people usually first notice Infantile spasms-broad thumbs syndrome?
How infantile spasms-broad thumbs syndrome is first noticed often begins in early infancy, when a baby starts having sudden clusters of brief jerking or bending spells called infantile spasms, sometimes around waking or falling asleep. Families or doctors may also notice unusually broad thumbs, and many babies show slowed development or loss of skills they had just started to gain. Because these spasms can be subtle at first and may look like startles or tummy crunches, the first signs of infantile spasms-broad thumbs syndrome are often recognized when the movements keep repeating or development does not seem to be moving forward as expected.
Types of Infantile spasms-broad thumbs syndrome
No distinct types of Infantile spasms-broad thumbs syndrome are widely recognized.
Can I slow down the onset of symptoms?
Probably not. Because infantile spasms-broad thumbs syndrome is a rare genetic condition that usually starts in early infancy, there is no good evidence that lifestyle changes or medicines can meaningfully delay when symptoms begin, so there are no proven ways to reduce the risk of onset or prevent the condition in a child who has it. What does help is early recognition and urgent treatment at the first signs of spasms or loss of skills, which may improve seizure control and support development for some children, even though it cannot promise a specific outcome.
What genetics can tell you about symptoms
Genetics can help explain why people with infantile spasms-broad thumbs syndrome may have a similar pattern of features, such as seizures starting in infancy, developmental differences, and unusually broad thumbs, but the exact mix of symptoms can still vary from one child to another. Even when the same gene is involved, genetic changes may influence which symptoms appear, how severe they are, and sometimes when they begin, although infantile spasms usually start early in life. Genetic testing can help confirm the diagnosis and guide care, but it usually cannot predict exactly how mild or severe symptoms will be in any one child.
Causes and risk factors
Infantile spasms-broad thumbs syndrome appears to be caused by a genetic change that affects development before birth. In the few families described, this change may be inherited or may happen for the first time in a child. Family history is the clearest known risk factor, especially if relatives have infantile spasms, broad thumbs or toes, or unexplained developmental delays. Lifestyle, diet, and everyday exposures are not known to be primary causes, though other health factors may affect how early symptoms of Infantile spasms-broad thumbs syndrome show up. Knowing your family history is a good first step.
What are the most common causes or risk factors?
Infantile spasms-broad thumbs syndrome is most often linked to a change in a gene involved in early growth and brain development, and in many families this change happens for the first time in the child rather than being inherited. The main known risk factor is a family history of the same rare genetic change, although that is uncommon, and there are no well-proven non-genetic risk factors such as diet, routine pregnancy exposures, or anything a parent did or did not do.
Environmental and biological risk factors
Infantile spasms-broad thumbs syndrome is so rare that clear non-genetic risk factors have not been mapped out. Most available evidence does not link it to specific pregnancy exposures, infections, or delivery complications. Awareness of both biological and environmental influences helps you feel prepared, but for this syndrome there is often no preventable trigger to identify.
No specific environmental exposure or non-genetic biological factor has been firmly shown to increase the chance of infantile spasms-broad thumbs syndrome. For many families, this means the condition appears unexpectedly, without a clear cause that could have been prevented.
Genetic risk factors
Infantile spasms-broad thumbs syndrome appears to have a genetic basis, but the exact cause has not been fully pinned down because only a small number of people have been reported. Most experts suspect a rare gene change, often one that starts for the first time in the affected child, although the pattern may not be the same in every family. In some cases, genetic testing can give a clearer picture of your personal risk.
Exact gene unknown: No single gene has been proven to explain all reported cases of Infantile spasms-broad thumbs syndrome. This means the genetic causes of Infantile spasms-broad thumbs syndrome are still being clarified.
New gene change: In many very rare genetic conditions, the change happens for the first time in the child rather than being inherited from a parent. This is one likely explanation for some cases of Infantile spasms-broad thumbs syndrome.
Inherited change: Some families may have an inherited genetic change, although this seems to be less common. If a parent carries the same change, the chance for another child to have the syndrome can be higher.
Parental mosaicism: Sometimes a parent carries the genetic change in only some of their cells and has mild or no symptoms. This can still increase recurrence risk, even when there is no obvious family history.
Lifestyle risk factors
Infantile spasms-broad thumbs syndrome is a rare genetic condition, so lifestyle habits do not cause it. Still, how lifestyle affects Infantile spasms-broad thumbs syndrome can matter for seizure control, day-to-day functioning, growth, and the risk of complications. The most relevant lifestyle factors are the routines and exposures that can trigger spasms, interfere with treatment, or support development and safety.
Irregular sleep, sleep deprivation, or frequent nighttime disruption can lower seizure threshold and make spasms harder to control in some children. A consistent sleep schedule and prompt attention to sleep problems may help reduce symptom worsening and daytime irritability.
Missed doses, sudden changes, or inconsistent timing of anti-seizure medicines can increase the chance of breakthrough spasms. Caregivers who follow the treatment plan closely may improve seizure stability and reduce emergency visits.
Poor hydration, reduced feeding, and delayed care during infections can stress the body and sometimes worsen seizures or recovery. Quick management of fever, fluids, and medical review can help limit complications in a child who is already neurologically vulnerable.
Feeding difficulties, poor calorie intake, or restrictive eating can worsen growth problems and make it harder for the child to tolerate illness or therapy. When feeding is optimized, children may have better energy, steadier development, and safer medication use.
Risk prevention
Infantile spasms-broad thumbs syndrome is a rare genetic condition, so there is usually no proven way to prevent the syndrome itself through diet, exercise, or other everyday habits. Prevention is mainly about lowering the chance of complications, getting seizures treated quickly, and supporting development as early as possible. If this condition has affected your family, genetic counseling can help clarify recurrence risk and reproductive options. Different people need different prevention strategies—there’s no single formula.
If there is a family history of Infantile spasms-broad thumbs syndrome, meeting with a genetics specialist before pregnancy may help you understand recurrence risk. This can also help families discuss testing choices and reproductive options in a clear, practical way.
Fast medical attention for the early symptoms of Infantile spasms-broad thumbs syndrome may help shorten the time to diagnosis and treatment. Treating infantile spasms promptly can lower the risk of ongoing seizures and may help protect development.
Regular visits with a child neurologist can help track seizure control and adjust treatment when needed. For many living with Infantile spasms-broad thumbs syndrome, close follow-up may reduce seizure-related setbacks and hospital visits.
Taking seizure medicines exactly as prescribed can help prevent missed doses, which may trigger more spasms or seizures. Caregivers should check with the medical team before stopping or changing any treatment.
Can you prevent Infantile spasms-broad thumbs syndrome?
No, there is no known way to prevent infantile spasms-broad thumbs syndrome. It is a rare genetic condition, so it is usually not caused by anything parents did or did not do before or during pregnancy. If this condition has happened in your family, meeting with a genetics specialist may help you understand the chance of it happening again, but it cannot guarantee prevention.
Transmission
Infantile spasms-broad thumbs syndrome is not infectious, so it cannot be caught from another person through touch, coughing, kissing, blood, food, or sex. It is a genetic or congenital condition, which means the underlying change is present from birth rather than something that spreads between people.
For many living with this condition, the genetic change may happen for the first time in the child, while in some families it may be passed down from a parent. Because this syndrome is very rare, the exact pattern can vary, and a genetics specialist can explain how Infantile spasms-broad thumbs syndrome is inherited and what that may mean for future pregnancies.
When to test your genes
Consider genetic testing as soon as an infant has spasms or seizures, developmental delay, and unusually broad thumbs or great toes, or if a close relative has similar features. Early testing can confirm the diagnosis, help guide seizure care and developmental support, and clarify recurrence risk for the family.
Diagnosis
Diagnosis of Infantile spasms-broad thumbs syndrome usually starts when a baby has brief, repeated jerking spells along with noticeable differences in the thumbs or big toes. Doctors often combine what they see on the physical exam with brain testing and genetic tests to confirm the cause. Getting a diagnosis is often a turning point toward answers and support.
Doctors look closely at seizure-like episodes, development, and body features such as broad thumbs or broad big toes. In a genetic diagnosis of Infantile spasms-broad thumbs syndrome, this pattern can provide an important early clue.
A careful description of the events helps doctors tell infantile spasms from reflux, startle reflexes, or other movements that can look similar. Videos recorded at home can be very helpful because the spells are often brief and happen in clusters.
An electroencephalogram, or EEG, records the brain’s electrical activity and is a key test when infantile spasms are suspected. Doctors look for patterns that support the diagnosis and help guide urgent treatment decisions.
Brain MRI is often used to check for structural changes or other causes of seizures. Imaging findings may be normal in some children, but the scan still helps rule out other conditions.
How is Infantile spasms-broad thumbs syndrome diagnosed?
Infantile spasms-broad thumbs syndrome is usually suspected when a baby has the typical seizure pattern of infantile spasms along with unusual physical features such as wide thumbs, and often developmental delays. Doctors usually confirm the spasms with an EEG, a painless test that records brain wave patterns, and they may also do a brain MRI, which is a scan of the brain, plus a careful physical and developmental exam. Genetic testing can help support the diagnosis and rule out similar conditions, but it is usually used alongside the baby’s symptoms, exam findings, and test results rather than by itself.
Stages of Infantile spasms-broad thumbs syndrome
Infantile spasms-broad thumbs syndrome does not have defined progression stages. This is because it is a rare genetic condition identified by a pattern of features, rather than a disease that is known to move through clear step-by-step phases over time. Early symptoms of Infantile spasms-broad thumbs syndrome often lead to evaluation in infancy, especially when spasms, delays in development, or unusually broad thumbs are noticed. Doctors usually start with a conversation about symptoms and development, then use a physical exam, brain wave testing for spasms, and often genetic testing to help confirm the diagnosis.
Outlook and prognosis
The outlook for infantile spasms-broad thumbs syndrome is variable but is often guarded because affected children typically have early-onset epileptic spasms and developmental delay that can be difficult to control. Prognosis depends largely on how well the seizures respond to treatment and on the severity of associated neurologic and developmental problems. Even when infantile spasms improve, many children continue to have intellectual disability, delayed speech and motor skills, and in some cases ongoing epilepsy later in childhood. Because this is an extremely rare disorder, published long-term outcome data are limited, and no reliable syndrome-specific life expectancy figures have been established. Mortality is not well defined, but severe uncontrolled epilepsy and complications related to underlying neurologic impairment can increase medical risk in the most affected individuals. Early diagnosis, prompt treatment of spasms, and coordinated developmental support offer the best chance of improving function and quality of life.
Long-term effects
For many living with Infantile spasms-broad thumbs syndrome, the biggest long-term effects are usually related to brain development, learning, and seizure history rather than the hand difference itself. Long-term effects vary widely, but many people have lasting developmental challenges that begin in infancy and continue through childhood and adult life. When families ask about the long-term effects of Infantile spasms-broad thumbs syndrome, doctors usually focus on development, communication, mobility, and whether seizures continue or return later.
Many people with Infantile spasms-broad thumbs syndrome have ongoing delays in learning, problem-solving, and day-to-day independence. The degree can range from milder learning needs to more significant intellectual disability.
Language development is often affected, and some children speak later than expected or use fewer words than other children their age. In more severe cases, communication may remain limited into later childhood or adulthood.
Infantile spasms can leave a lasting effect on brain development, and some people go on to have other seizure types later in life. Others may have a quieter seizure course, so the long-term picture can differ from one person to another.
Sitting, walking, balance, and coordinated hand use may develop more slowly. Broad thumbs can add to fine motor difficulty, so tasks like grasping small objects, buttoning clothes, or writing may be harder.
How is it to live with Infantile spasms-broad thumbs syndrome?
Living with Infantile spasms-broad thumbs syndrome often means coping with early-onset seizures and significant developmental challenges, so daily life may include frequent medical visits, therapies, and close watching for changes in movement, feeding, sleep, or alertness. Many living with this condition need substantial hands-on support with communication, learning, and everyday care, although the exact level of need can vary from one child to another. For families and other close caregivers, this can reshape routines, work, sleep, and emotional life, but steady support from neurology, developmental specialists, therapists, and community resources can make day-to-day life more manageable and help each child reach their own potential.
Treatment and drugs
Treatment for Infantile spasms-broad thumbs syndrome usually focuses first on stopping the infantile spasms as quickly as possible, because ongoing spasms can affect development. Doctors often use anti-seizure treatments such as steroid therapy, including adrenocorticotropic hormone or prednisolone, and in some cases vigabatrin, with the choice depending on the child’s seizure pattern, test results, and overall health. Not every treatment works the same way for every person, so the care team may adjust medicines or try another option if the spasms do not improve or side effects become a problem. Alongside seizure treatment, many children with Infantile spasms-broad thumbs syndrome also benefit from early supportive care such as physical, occupational, and speech therapy, plus regular follow-up with neurology and developmental specialists.
Can you cure Infantile spasms-broad thumbs syndrome?
No, there is currently no cure for infantile spasms-broad thumbs syndrome. Treatment cannot remove the underlying condition, but it can help control the spasms, treat related health problems, and support a child’s development with therapies and specialist care. Because this condition can affect each child differently, care is usually tailored to the child’s own symptoms and needs.
Non-drug treatment
Daily care for infantile spasms-broad thumbs syndrome usually involves more than seizure medicine alone. Many living with infantile spasms-broad thumbs syndrome benefit from therapies that support movement, feeding, communication, and learning from an early age. Supportive therapies can improve comfort, help prevent complications, and make day-to-day routines easier for families. Because the condition can affect each child differently, treatment plans are usually tailored over time, especially after the early symptoms of infantile spasms-broad thumbs syndrome become clear.
Developmental therapy started in infancy can support motor, play, and learning skills as a child grows. For many, treatment begins not at the pharmacy, but with early intervention services at home or in the community.
Physical therapy can help with stiffness, low muscle tone, balance, and delayed movement skills. It also helps with positioning, stretching, and safe ways to practice rolling, sitting, standing, or walking.
Occupational therapy focuses on hand use, daily activities, and practical skills such as grasping toys, dressing, and sitting support. This can be especially helpful when broad thumbs or other hand differences affect fine motor tasks.
Speech-language therapy may help with communication, swallowing, and feeding problems. Some non-drug options are delivered by specialists, including feeding therapy for coughing, choking, or trouble handling different food textures.
Your genes may have an impact on how drugs work for you
For families dealing with infantile spasms with broad thumbs, the biggest day-to-day question is often whether seizure treatment will work quickly and how well it will be tolerated. In this condition, the main gene change is most helpful for explaining the syndrome itself, not for predicting exactly how common spasm medicines will work, and at this point there are no widely used gene-based rules that reliably tell doctors which medicine will work best or cause side effects. Even so, response can vary from child to child, so doctors usually watch closely and adjust treatment based on how well the spasms come under control and how the child is doing overall.
Pharmacological treatments
Treatment for Infantile spasms-broad thumbs syndrome usually focuses on controlling the infantile spasms, since there is no medicine that changes the underlying syndrome itself. The main drugs used are hormone-based treatments such as ACTH or prednisolone, and in some children vigabatrin is also used. Not everyone responds to the same medication in the same way. Other seizure medicines may be considered if the first treatment does not stop the spasms and improve the EEG pattern quickly.
ACTH is one of the main first treatments for infantile spasms and is given by injection for a short course. It can work quickly, which matters because early treatment for infantile spasms-broad thumbs syndrome may help limit ongoing effects from repeated spasms. Doctors monitor blood pressure, blood sugar, infection risk, and irritability during treatment.
Prednisolone is a steroid taken by mouth and is another common first-line option for infantile spasms. Some centers use it instead of ACTH because it is easier to give and may be more available. Careful follow-up is still needed because it can cause side effects similar to other steroid treatments.
Vigabatrin is an anti-seizure medicine that is often used for infantile spasms, sometimes alone and sometimes after or with steroid treatment depending on the situation. It is especially well known in spasms linked to certain other conditions, but it may still be considered here. Eye monitoring is important with longer use because vigabatrin can affect peripheral vision.
If spasms continue, doctors may try other anti-seizure medicines such as topiramate, valproate, levetiracetam, clobazam, or zonisamide. These are usually backup options when standard first treatments do not work well enough. Response can vary, and the goal is to stop spasms completely rather than just reduce them.
Genetic influences
Infantile spasms-broad thumbs syndrome appears to have a strong genetic basis, meaning it is likely linked to a change in a gene involved in early brain and body development. The exact genetic cause of Infantile spasms-broad thumbs syndrome has not been clearly established for everyone reported with it, so doctors often recognize it by its pattern of symptoms and physical features rather than by one confirmed gene in all cases. Family history is one of the strongest clues to a genetic influence. Even so, some children with Infantile spasms-broad thumbs syndrome are the first in their family to be diagnosed, which can happen when a new gene change begins in the child for the first time. Because this condition is so rare, a genetics evaluation may help clarify the likely cause, talk through what it could mean for siblings or future pregnancies, and guide testing when it makes sense.
Is Infantile spasms-broad thumbs syndrome genetic?
Genetics are very important in Infantile spasms-broad thumbs syndrome, because it is usually caused by a disease-causing gene change. In many families, this change happens for the first time in the child, rather than being inherited.
Having a genetic risk is not necessarily a diagnosis
Genetic variants are common across the general population and are a normal feature of human biology. Most do not have a direct effect on health and simply add to the natural differences seen among people. For many genes, having a variant associated with a condition suggests a possible link rather than a certain diagnosis, especially when several genes and environmental factors are involved. In some situations, though, one well-understood variant in a particular gene may be enough to confirm a diagnosis.
Pharmacogenetics—how genetics influence drug effects
In Infantile spasms-broad thumbs syndrome, the genetic change matters because it can show that the spasms are part of a wider syndrome, not just a seizure problem on its own. That can help doctors move more quickly toward standard infantile spasm treatments, such as hormone-based treatment or vigabatrin, while also planning developmental, feeding, and therapy support early. Not every difference in response is genetic, but finding the underlying gene can help the care team judge whether seizures may be harder to control and watch more closely for side effects or other medical issues linked with the syndrome. For many families, this also means fewer unnecessary tests and a clearer idea of what the early symptoms of Infantile spasms-broad thumbs syndrome may lead to over time. Right now, genetics usually guides diagnosis, monitoring, and overall care planning more than it points to one special drug, so treatment is still adjusted to the child’s symptoms and how well the spasms respond.
Interactions with other conditions
In daily life, the biggest challenge is often not the broad thumbs themselves but how Infantile spasms-broad thumbs syndrome can occur alongside other health problems that affect comfort, feeding, breathing, and development. The seizure disorder at the center of this condition may be harder to manage if a child is also dealing with fever, reflux, poor sleep, or another illness that puts stress on the body, and some families first notice this when spasms seem worse during an infection. To understand overall health, it’s useful to see how conditions overlap. Many living with Infantile spasms-broad thumbs syndrome also need monitoring for developmental delay, low muscle tone, feeding problems, or vision and hearing differences, because each of these can add to day-to-day difficulties and sometimes make the early symptoms of Infantile spasms-broad thumbs syndrome less straightforward to spot. Recurrent chest infections or aspiration from swallowing problems can further affect energy and recovery, while long-term epilepsy treatment may need extra care if other medical issues are present. Interactions can look very different from person to person, so care is usually best coordinated across neurology, pediatrics, and therapy teams.
How genes can cause diseases
Humans have more than 20,000 genes, each carrying out one or a few specific functions in the body. One gene instructs the body to digest lactose from milk, another tells the body how to build strong bones and another prevents the body's cells from beginning to multiply uncontrollably and developing into cancer. As all of these genes combined are the building instructions for our body, a defect in one of these genes can have severe health consequences.
Through decades of genetic research, we know the genetic code of any healthy/functional human gene. We have also identified that in certain positions on a gene, some individuals may have a different genetic letter from the one you have. We call these hotspots "Genetic Variations" or "Variants" in short. In many cases, studies have been able to show that having the genetic letter "G" in the position makes you healthy, but having the letter "A" in the same position disrupts the gene function and causes a disease. Genopedia allows you to view these variants in genes and summarizes all that we know from scientific research, which genetic letters (Genotype) have good or bad consequences on your health or on your traits.
What other conditions can cause similar symptoms to Infantile spasms-broad thumbs syndrome?
Other causes of infantile spasms, which are sudden seizure clusters in babies, can look very similar at first, especially tuberous sclerosis, Down syndrome, and problems from a brain injury or a brain that developed differently before birth. Doctors may also consider a rare condition called Rubinstein-Taybi syndrome, because it can also cause broad thumbs, delayed development, and seizures.
History
Families often first notice the day-to-day signs rather than the name: a baby having brief, repeated jerks or stiffening spells, then later being found to have unusually broad thumbs and sometimes broad big toes. Today this pattern is known as Infantile spasms-broad thumbs syndrome, but it took time for doctors to realize these features could belong to the same condition rather than being separate problems.
In the earlier medical literature, doctors tended to describe the seizures, development, and physical features one piece at a time. Some children were first recognized because of infantile spasms, a seizure type that usually begins in the first year of life, while others drew attention because of their hand and foot differences or delays in development. Once considered rare, now recognized as a distinct condition, Infantile spasms-broad thumbs syndrome became clearer as more case reports were compared and patterns began to match.
As medical science evolved, better brain-wave testing and brain imaging helped doctors identify infantile spasms more accurately, including the early symptoms of Infantile spasms-broad thumbs syndrome. Over time, careful physical exams also showed that broad thumbs and related features were not incidental in some children, but part of the broader picture. This made diagnosis more consistent and helped families get more focused care.
Later research showed that Infantile spasms-broad thumbs syndrome has an underlying genetic basis, which helped confirm that the seizure pattern and physical features can stem from the same medical condition. Not every early description was complete, yet together they built the foundation of today’s knowledge. Even now, the syndrome can vary from one child to another, so its history is still being refined as clinicians learn from newly diagnosed families and longer-term follow-up.