Developmental and epileptic encephalopathy 90 is a rare brain disorder that usually begins in infancy or early childhood. It causes frequent seizures and can affect development, movement, learning, and communication. Many living with Developmental and epileptic encephalopathy 90 have lifelong needs, and the early symptoms of Developmental and epileptic encephalopathy 90 can vary from one child to another. Not everyone will have the same experience. Treatment often includes anti-seizure medicines and supportive therapies such as physical, occupational, speech, and feeding care, and the outlook depends on how severe the condition is and how well seizures and other complications can be managed.
How many people live with Developmental and epileptic encephalopathy 90?
There are no reliable published estimates for how many people are living with developmental and epileptic encephalopathy 90 worldwide or in the United States. Rare-disease references such as Orphanet and OMIM describe it as an ultra-rare condition, but they do not provide a confirmed global or U.S. population count (Orphanet, 2024; OMIM, 2024).
Overview
Developmental and epileptic encephalopathy 90Symptoms
Developmental and epileptic encephalopathy 90 often causes early-life seizures and delayed development. Many living with Developmental and epileptic encephalopathy 90 have low muscle tone, feeding trouble, and learning difficulties. Signs vary, but early symptoms of Developmental and epileptic encephalopathy 90 usually begin in infancy.
Outlook and prognosis
In developmental and epileptic encephalopathy 90, outlook varies, but many children have ongoing seizures, developmental delays, and lifelong support needs. Some gain skills with treatment, while others remain medically fragile. Regular specialist care can improve comfort, safety, and daily function.
Causes and risk factors
Developmental and epileptic encephalopathy 90 is caused by a change in the CLTC gene, usually new in the child rather than inherited. Family history can occasionally raise risk, while other factors may affect severity or complications but do not cause it.
Genetic influences
Genetics are central to Developmental and epileptic encephalopathy 90, which is usually caused by a disease-causing change in a single gene. These genetic variations often arise new in the child, though inherited cases can also occur.
Diagnosis
Developmental and epileptic encephalopathy 90 is diagnosed by reviewing seizure history, development, and neurologic exam. Doctors also use EEG and brain imaging. Genetic diagnosis of Developmental and epileptic encephalopathy 90 confirms the condition and helps rule out similar disorders.
Treatment and drugs
Developmental and epileptic encephalopathy 90 is usually managed with anti-seizure medicines and regular neurology care. Many children also benefit from physical, speech, and feeding support. Treatment is individualized, and a genetics team may guide choices and monitoring.
Symptoms
Developmental and epileptic encephalopathy 90 usually becomes noticeable early in life, often when seizures and delays in learning new skills start to affect daily routines. The early features of Developmental and epileptic encephalopathy 90 may include seizures, low muscle tone, and slower development of sitting, walking, or speech. Some children also have feeding, movement, sleep, or behavior difficulties. Features vary from person to person and can change over time.
In Developmental and epileptic encephalopathy 90, seizures are often one of the most noticeable signs. They can look different from child to child, including staring spells, body stiffening, jerking, or reduced awareness, and they may interrupt sleep, play, and learning.
Many children with Developmental and epileptic encephalopathy 90 reach milestones later than expected, such as rolling, sitting, walking, or using their hands well. Learning can be slow, and some children may lose skills during periods when seizures are more difficult to control.
Speech and language are often delayed, and some children use few words or rely more on gestures, sounds, or communication devices. Day to day, it can feel like basic needs and feelings are harder to express.
Low muscle tone can make a child seem floppy, tire easily, or need extra support for sitting and standing. This can make everyday movement, dressing, and play more difficult.
How people usually first notice Developmental and epileptic encephalopathy 90?
For many families, the first signs of Developmental and epileptic encephalopathy 90 are seizures that begin in infancy or early childhood, sometimes appearing as staring spells, stiffening, jerking, or brief episodes where a baby suddenly seems unresponsive. It is also often first noticed when a child is not gaining skills as expected, such as head control, sitting, babbling, or later language and movement, and some children may seem unusually floppy or have feeding difficulties early on. Because this condition is rare and symptoms can vary, doctors usually begin to suspect it when seizures and developmental concerns show up together, then confirm the cause with a neurological evaluation and genetic testing.
Types of Developmental and epileptic encephalopathy 90
No distinct types of Developmental and epileptic encephalopathy 90 are widely recognized.
Can I slow down the onset of symptoms?
No. For Developmental and epileptic encephalopathy 90, there is currently no good evidence that lifestyle changes, diet, supplements, or other everyday steps can meaningfully delay when symptoms begin, because this is a rare genetic condition that usually starts early in life. There is also no proven preventive medicine or screening that can stop it from starting, although early care from a child neurology team can help manage seizures and support development once symptoms appear; research is ongoing, and getting help early may still improve day-to-day care even though it cannot promise a later onset or prevent the condition.
What genetics can tell you about symptoms
Genetics can help explain why developmental and epileptic encephalopathy 90 can look different from one child to another, even when the diagnosis sounds the same. In general, the specific disease-causing change in the gene linked to this condition can influence which symptoms show up, how early seizures and developmental problems begin, and how severe they become, although there can still be a wide range from person to person. This means genetic testing may give families and doctors a clearer idea of the expected pattern of seizures, learning and movement difficulties, and overall day-to-day needs, but it usually cannot predict every symptom exactly.
Causes and risk factors
Most cases of Developmental and epileptic encephalopathy 90 are caused by an inherited or new mutation present from the start of life, and this changes how the brain develops and how nerve cells signal. The mutation is often new in the child, but family history becomes an important risk factor when it runs in a family. Nothing a parent did during pregnancy, feeding, or day to day care is known to directly cause this condition. Fever, infections, missed seizure medicine, and poor sleep do not cause Developmental and epileptic encephalopathy 90, but they can trigger seizures or make them harder to control. Genetic testing for Developmental and epileptic encephalopathy 90 can help confirm the cause and show whether future children may also be at risk.
What are the most common causes or risk factors?
Developmental and epileptic encephalopathy 90 is mainly a genetic condition, caused by a harmful change in a gene that is important for early brain development and for the signals brain cells use to communicate. In many children, this change happens for the first time in them, but in some families it is passed down, so a family history of similar early seizures or developmental delays can raise the chance. There are no well-established lifestyle, pregnancy, or environmental risk factors known to be a common cause of this specific condition.
Environmental and biological risk factors
If you are looking into developmental and epileptic encephalopathy 90 risk factors, it helps to know that clear outside causes have not been found. Some risks are carried inside the body, others come from the world around us. For developmental and epileptic encephalopathy 90, doctors mainly think about very early body-based changes rather than anything routine in pregnancy or daily life. Research on other possible influences is still limited because the condition is rare.
In rare conditions like developmental and epileptic encephalopathy 90, older father age may slightly raise the chance of a new change being present from conception. This is a possible biological influence, not a common or strongly predictive cause.
No food, everyday activity, or common household exposure has been shown to specifically cause developmental and epileptic encephalopathy 90. For many families, there is no clear environmental trigger to point to.
High-dose radiation and some industrial toxins can affect a developing baby in general. Even so, they have not been confirmed as specific risk factors for developmental and epileptic encephalopathy 90.
Problems during pregnancy or delivery are not considered usual causes of developmental and epileptic encephalopathy 90. When they occur, doctors usually evaluate them separately unless there is strong evidence of a direct effect on early brain development.
Genetic risk factors
For many families, understanding the genetic causes of Developmental and epileptic encephalopathy 90 can make a confusing diagnosis easier to process. This condition is usually tied to a harmful change in a single gene that helps brain cells develop and send signals. Most often, that change is found through genetic testing after early seizures and developmental delays begin. The chance of it happening again in a family depends on whether the variant was new in the child or inherited.
Single-gene change: Developmental and epileptic encephalopathy 90 is linked to a harmful DNA change in one gene that is important for brain development and brain-cell signaling. When that gene does not work properly, seizures and developmental problems can begin very early in life.
De novo variant: In many children, the genetic change is new and was not inherited from either parent. This is called a de novo variant, and it usually means nothing during pregnancy or early care caused the condition.
Inherited change: In some families, the variant can be passed down from a parent who is mildly affected or has no obvious symptoms. The chance of this depends on the exact inheritance pattern found on genetic testing.
Parental mosaicism: Sometimes a parent carries the variant in only some egg or sperm cells, even if their blood test is normal. This can raise the chance of another child having Developmental and epileptic encephalopathy 90, so recurrence risk is best reviewed with a genetics specialist.
Lifestyle risk factors
Developmental and epileptic encephalopathy 90 is a genetic neurologic disorder, so lifestyle habits do not cause it. However, how lifestyle affects Developmental and epileptic encephalopathy 90 can matter for seizure control, daily functioning, comfort, and the risk of complications. The most relevant factors are those that change sleep, medication consistency, illness exposure, nutrition, hydration, and safety during seizures.
Irregular sleep or sleep loss can lower the seizure threshold and make episodes more likely in Developmental and epileptic encephalopathy 90. A consistent sleep schedule and a calm bedtime routine may help reduce seizure provocation and daytime irritability.
Missing antiseizure medicines, changing doses without guidance, or giving doses at inconsistent times can lead to breakthrough seizures. Reliable dosing routines can support steadier seizure control and may reduce emergency visits.
Viral infections, fever, and poor recovery habits can increase seizure risk and worsen overall neurologic stress. Good hand hygiene, prompt fever management as advised by the care team, and adequate rest during illness may help limit setbacks.
Feeding difficulties, poor intake, or unplanned weight loss can worsen weakness, fatigue, and recovery after seizures. Nutrition plans tailored to swallowing ability and energy needs can support growth, strength, and tolerance of treatments.
Risk prevention
For developmental and epileptic encephalopathy 90, true prevention of the condition itself is usually not possible because it is a genetic condition present from the start. In daily life, prevention is mostly about lowering the risk of seizures, developmental setbacks, injuries, and other complications, while supporting growth and comfort as much as possible. Many living with developmental and epileptic encephalopathy 90 do best with a plan that combines regular medical care, trigger avoidance, and practical safety steps at home and school. Prevention is flexible—it adapts to your life and health background.
Taking seizure medicine exactly as prescribed is one of the main ways to reduce seizure burden in developmental and epileptic encephalopathy 90. Missed doses can make seizures more likely, so routines, pill boxes, and caregiver reminders often help.
Regular visits help the care team adjust treatment, watch for side effects, and respond if seizures change over time. This can also help catch early symptoms of developmental and epileptic encephalopathy 90 that need added support, such as feeding trouble or loss of skills.
Some people with developmental and epileptic encephalopathy 90 are more likely to have seizures with poor sleep, illness, fever, flashing lights, or missed meals. Keeping sleep regular and treating infections or fever promptly may lower day-to-day risk.
A written seizure action plan can help families, school staff, and other caregivers know when to give rescue medicine and when to call emergency services. Quick action may reduce the chance of long seizures and related complications.
Can you prevent Developmental and epileptic encephalopathy 90?
Usually, no. Developmental and epileptic encephalopathy 90 is most often linked to a change in a gene from very early in development, so there is not a proven way to prevent the condition itself. If it has affected your family, genetic counseling before pregnancy may help you understand the chance of it happening again and talk through testing options.
Transmission
Developmental and epileptic encephalopathy 90 is not contagious, so it cannot be spread by touch, coughing, kissing, shared food, or everyday contact. Instead, genetic transmission of Developmental and epileptic encephalopathy 90 happens through a change in a gene.
How Developmental and epileptic encephalopathy 90 is inherited can vary: in some families the gene change is passed down from a parent, while in others it appears for the first time in the child as a new genetic change. Because of that, the chance of it happening again in a future pregnancy depends on the exact test result and family history.
When to test your genes
Consider genetic testing early if a baby or child has unexplained seizures, developmental delay, developmental regression, or an abnormal EEG, especially if standard evaluations do not find a cause. Testing can help confirm developmental and epileptic encephalopathy 90, guide treatment choices, and clarify family recurrence risk.
Diagnosis
Developmental and epileptic encephalopathy 90 is usually suspected when a baby or child has seizures along with delays in development, changes in muscle tone, or unusual movement patterns. Doctors look at the overall pattern over time, then use brain-wave testing, brain imaging, and genetic tests to confirm the diagnosis of developmental and epileptic encephalopathy 90. Getting a diagnosis is often a turning point toward answers and support.
Doctors ask when seizures began, what the episodes look like, and how development has changed over time. A detailed pregnancy, birth, medical, and family history can help show whether this condition fits the child’s overall pattern.
The exam looks for differences in muscle tone, reflexes, movement, growth, and alertness. These clinical features can support the diagnosis and may also help rule out other neurologic conditions.
An EEG records the brain’s electrical activity and is a key test when seizures are suspected. In many living with developmental and epileptic encephalopathy 90, EEG findings help show that epilepsy is part of the condition, even though the pattern can vary from child to child.
An MRI creates detailed pictures of the brain to check for structural changes or other causes of seizures and developmental problems. The scan may be normal in some children, but it is still useful in the diagnostic workup.
How is Developmental and epileptic encephalopathy 90 diagnosed?
Doctors usually diagnose developmental and epileptic encephalopathy 90 by putting together the story of a child’s seizures and development, the exam findings, and test results such as a brain wave test called an EEG and a brain scan such as MRI. Because several conditions can look similar, doctors may also do blood or urine tests to rule out other causes, and genetic testing can help confirm the diagnosis by finding the related gene change. The diagnosis is usually made by a child neurology team, often with help from genetics specialists.
Stages of Developmental and epileptic encephalopathy 90
Developmental and epileptic encephalopathy 90 does not have defined progression stages. This is because it is not usually described as moving through clear step-by-step phases; instead, symptoms can vary from one child to another and may change over time depending on seizure control, development, and overall health. Doctors usually start with a conversation about seizures, development, and the early symptoms of Developmental and epileptic encephalopathy 90, then combine this with a physical exam, brain wave testing, brain imaging, and genetic testing. Follow-up care usually focuses on tracking seizures, development, movement, feeding, sleep, and day-to-day function so treatment can be adjusted as needs change.
Outlook and prognosis
The outlook for people with developmental and epileptic encephalopathy 90 is generally guarded, because seizures often begin early in life and are commonly accompanied by persistent developmental delay, intellectual disability, and limited speech or motor progress. Some children have seizures that improve over time or become more manageable with treatment, but many continue to have difficult-to-control epilepsy and lifelong neurologic impairment. Developmental gains are usually slow, and many affected individuals need ongoing support for learning, behavior, mobility, and daily activities. Because this is a very rare condition, long-term survival data are limited, and a precise life expectancy is not well established. Mortality appears to depend largely on seizure severity, complications such as status epilepticus or accidents, feeding and respiratory problems, and the burden of associated medical issues rather than on a single predictable course.
Long-term effects
For many families, the long-term effects of developmental and epileptic encephalopathy 90 can shape daily life from infancy onward. In developmental and epileptic encephalopathy 90, long-term features often involve development, seizures, movement, feeding, and overall health, but the pattern and severity can differ widely. Long-term effects vary widely, and some children have major care needs while others gain skills more steadily over time. Many of these effects continue into adolescence and adulthood.
Many living with developmental and epileptic encephalopathy 90 have lasting delays in speech, learning, and motor skills. Some children may sit, walk, or communicate later than expected, and some may remain dependent on others for most daily activities.
Seizures may continue over many years, even if they change in type or become less frequent with age. Ongoing seizure activity can affect safety, learning, sleep, and overall brain function.
Long-term features can include low muscle tone, stiffness, poor balance, or unusual movements. For many, this can mean trouble with sitting, walking, hand use, or keeping up with everyday physical tasks.
Some children have long-term trouble with sucking, chewing, or swallowing safely. This can lead to poor weight gain, slow growth, choking risk, or a need for tube feeding in more severe cases.
How is it to live with Developmental and epileptic encephalopathy 90?
Living with developmental and epileptic encephalopathy 90 often means managing frequent seizures along with serious challenges in development, movement, learning, and communication, so daily life may revolve around medicines, therapy visits, close supervision, and adapting routines for safety. Many living with this condition need help with eating, sleep, mobility, and everyday tasks, although the exact pattern can vary from one child to another. For families and other caregivers, this can be physically and emotionally demanding, with constant watchfulness, disrupted sleep, and the need to coordinate medical care, school supports, and home life. Even so, consistent support, seizure care, and tailored therapies can help people with DEE90 stay as comfortable, engaged, and connected as possible.
Treatment and drugs
Developmental and epileptic encephalopathy 90 is usually treated with a mix of seizure care and support for learning, movement, and daily function, because the condition affects more than seizures alone. Treatment often looks different for each person, but many people with Developmental and epileptic encephalopathy 90 are given anti-seizure medicines, and some may also be offered a special high-fat diet, rescue medicine for long seizures, or other options if seizures are hard to control. Since early symptoms of Developmental and epileptic encephalopathy 90 often begin in infancy or childhood, care commonly involves a team that may include a neurologist, physical, occupational, and speech therapists, and other specialists based on the child’s needs. Supportive care can make a real difference in how you feel day to day, and regular follow-up helps doctors adjust treatment over time to balance seizure control, side effects, and development.
Can you cure Developmental and epileptic encephalopathy 90?
No, there is no cure right now for developmental and epileptic encephalopathy 90. Treatment cannot remove the condition, but it can help control seizures as much as possible and support day-to-day needs like development, movement, feeding, sleep, and comfort. Many living with this condition need a mix of seizure medicines, therapy, and ongoing care from specialists, with treatment tailored to how the condition affects them.
Non-drug treatment
Living with Developmental and epileptic encephalopathy 90 often means needing support for seizures, movement, feeding, sleep, and learning at the same time. For many, treatment begins not at the pharmacy, but with therapies and routines that help daily life run more smoothly. Because symptoms vary, the best non-drug treatment for Developmental and epileptic encephalopathy 90 is usually a personalized mix of rehabilitation, nutrition support, school services, and seizure-safety planning. These approaches do not cure the condition, but they can improve comfort, function, and quality of life.
Physical therapy can help with muscle stiffness, poor balance, delayed motor skills, and joint tightness. Many living with Developmental and epileptic encephalopathy 90 use it to practice sitting, standing, walking, or safe transfers. Braces, seating supports, or standing frames may be added when needed.
Occupational therapy focuses on everyday skills such as hand use, dressing, positioning, and play. It can also help with adaptive equipment for feeding, bathing, and other daily tasks. Some strategies can slip naturally into your routine—like practicing grasping during meals or play.
Speech and language therapy may support communication, even when spoken language is very limited. Therapists may introduce gestures, picture boards, or speech devices so children can express needs more easily. Feeding and swallowing work is often included when coughing, choking, or long mealtimes are a problem.
A dietitian can help if there are feeding difficulties, poor weight gain, reflux, or constipation. In some children with hard-to-control seizures, a ketogenic diet or related medical diet may be considered with close specialist supervision. Not every approach works the same way, so nutrition plans are usually adjusted over time.
Your genes may have an impact on how drugs work for you
For people living with developmental and epileptic encephalopathy 90, the genetic change causing the condition can shape how well seizure medicines work, so one medicine may help reduce seizures in some while another may have little effect or even make seizure control harder. In day-to-day life, this can mean a long period of careful trial and adjustment, where doctors watch closely for both seizure improvement and side effects such as sleepiness, poor feeding, or changes in alertness. At this time, there is no widely used genetic test that can reliably predict the best medicine for this specific condition, but the underlying genetic diagnosis can still help guide treatment choices and set realistic expectations.
Pharmacological treatments
For many living with developmental and epileptic encephalopathy 90, treatment usually focuses on controlling seizures as safely as possible, even though no single medicine is known to work best for everyone. Doctors often try antiseizure medicines based on the seizure pattern, the child’s age, and how well each drug is tolerated. Not everyone responds to the same medication in the same way. In some children, more than one medicine is needed over time.
Valproate is a broad antiseizure medicine that may help when developmental and epileptic encephalopathy 90 causes several seizure types. It is often considered when seizures are frequent, but it needs monitoring because it can affect the liver, blood counts, and weight.
Levetiracetam is commonly used because it is available in child-friendly forms and does not usually require complex blood-level monitoring. Some children do well on it, while others may have irritability, mood changes, or sleep disruption.
Clobazam, and sometimes clonazepam, can reduce seizure burden in some people with developmental and epileptic encephalopathy 90. These medicines may cause sleepiness, drooling, or tolerance over time, meaning they may become less effective after longer use.
Topiramate or zonisamide may be added when seizures continue despite first treatments. These medicines can sometimes help the early symptoms of developmental and epileptic encephalopathy 90 related to seizures, but they may also affect appetite, alertness, or sweating.
Genetic influences
When seizures begin early and development does not move forward as expected, families often want to know whether there is a clear genetic reason. Developmental and epileptic encephalopathy 90 is a genetically defined subtype caused by harmful changes in the UGDH gene. A carrier means you hold the gene change but may not show symptoms, so parents can pass on the condition without knowing they carry the change themselves. When both copies of UGDH are affected, brain development and brain cell communication can be disrupted, which helps explain the combination of seizures and developmental problems. Genetic testing for Developmental and epileptic encephalopathy 90 can confirm the diagnosis and help families understand future pregnancy chances and whether other relatives may also be carriers.
Is Developmental and epileptic encephalopathy 90 genetic?
Genetics are central to Developmental and epileptic encephalopathy 90, which is usually caused by a disease-causing change in a single gene. These genetic variations often arise new in the child, though inherited cases can also occur.
Having a genetic risk is not necessarily a diagnosis
In the general population, genetic variants are common and are a normal part of human biology. Most do not directly affect health and simply reflect the natural range of human diversity. For many genes, having a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when several genes and environmental factors are involved. In some cases, though, a single well-characterized variant in a specific gene can be enough to confirm a diagnosis.
Pharmacogenetics—how genetics influence drug effects
Because developmental and epileptic encephalopathy 90 starts with an underlying gene change, the genetic finding can help the care team choose treatment more thoughtfully rather than relying only on trial and error. In day-to-day care, this usually means matching anti-seizure medicines and supportive therapies to the seizure pattern, developmental needs, and the known behavior of that specific genetic form of epilepsy. There is not one best treatment for developmental and epileptic encephalopathy 90 that works for everyone, but the genetic result may help doctors judge which medicines are more likely to help, which ones may be less useful, and when to consider diet therapy, devices, or research studies. Genetics is only one factor, and age, seizure type, other health problems, and side effects still matter when choosing medicines. Some people also carry separate genetic differences that affect how quickly their body processes certain drugs, which can change the dose needed or the chance of side effects. For many living with this condition, genetic testing is most helpful because it confirms the diagnosis, guides treatment planning, and helps families have a clearer discussion with their neurology team about medications for developmental and epileptic encephalopathy 90.
Interactions with other conditions
For many families, Developmental and epileptic encephalopathy 90 can affect far more than seizures alone, because other health problems may add to day-to-day care. Many living with Developmental and epileptic encephalopathy 90 also have developmental delay, low muscle tone, feeding difficulties, or movement problems, and these can make illness, recovery, and treatment more complicated. Doctors call it a “comorbidity” when two conditions occur together. For example, if a child with Developmental and epileptic encephalopathy 90 also has trouble swallowing or poor muscle control, chest infections may be more likely, and seizures can become harder to manage when the child is sick or not sleeping well. Some may also have autism-like social and communication difficulties or sleep problems, which can overlap with the condition and change what support is most helpful at home, school, and clinic visits. Because the early symptoms of Developmental and epileptic encephalopathy 90 can overlap with other neurologic conditions, careful follow-up helps doctors sort out which changes are part of the condition itself and which may come from another illness.
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 Developmental and epileptic encephalopathy 90?
Other conditions that can look similar to developmental and epileptic encephalopathy 90 include other rare genetic epilepsy syndromes, brain problems present from birth, and brain injury from causes such as low oxygen around the time of birth. Some metabolic conditions, as well as cerebral palsy or autism together with seizures and developmental delay, can also seem similar at first. Because these conditions can overlap so much, doctors usually need a careful history, brain wave testing, brain scans, and genetic testing to tell them apart.
History
For many families, the story begins not with a name, but with a baby or young child who has seizures early in life and then seems to fall behind with development. What doctors now call developmental and epileptic encephalopathy 90, or DEE90, became easier to recognize only after specialists started comparing patterns across children who had similar seizure types, learning difficulties, and brain-related symptoms.
Earlier in medicine, many of these children would have been placed into broader epilepsy or developmental delay groups rather than given a more specific diagnosis. As medical science evolved, doctors came to understand that some severe epilepsies do more than cause seizures alone; they can also affect how the brain develops over time. That shift led to the wider use of the term developmental and epileptic encephalopathy, which reflects both parts of the condition: the developmental challenges and the epilepsy.
DEE90 is one of the more recently described forms within that larger group. In recent decades, awareness has grown as improved brain testing and genetic research helped specialists separate conditions that once looked similar on the surface. For families, this has meant that a child’s early symptoms of DEE90 may now be linked to a clearer diagnosis than was possible in the past.
The history of DEE90 is therefore closely tied to the broader history of childhood epilepsy care. Doctors first relied mainly on what they could see in day-to-day life, such as seizure patterns, delayed milestones, low muscle tone, or movement and behavior changes. Later, electroencephalogram testing, brain imaging, and research studies made it possible to define more precise subtypes, including DEE90.
This growing understanding has also changed care. Even when there is not yet a cure, having a recognized diagnosis can help families make sense of symptoms, connect with specialists, and plan support for feeding, learning, mobility, and seizure treatment. For many living with DEE90, that clearer medical picture is an important part of the condition’s more recent history.