Dravet Syndrome In Babies: Causes, Symptoms And Treatment

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Dravet syndrome (DS) in babies is a rare genetic condition, previously referred to as severe myoclonic epilepsyⁱA brain-related phenomenon characterized by uncontrollable movements and loss of consciousness of infancy (SMEI) or epilepsy with polymorphic seizuresⁱA type of seizure characterized by a varied pattern of body movements

. It is characterized by temperature-sensitive epileptic seizures that usually begin in the first year of a baby’s life (1). Most individuals (more than 80%) with DS develop a mutation in a specific gene. Although, in some cases, mutations in more than a single gene may lead to the development of the syndrome (2). However, having a genetic mutation isn’t enough for the diagnosis.

Keep reading to learn the causes, symptoms, diagnosis, treatment, and management of Dravet syndrome in babies.

Did you know?

Referred to as a complex genetic form of epilepsy, DS was first identified by Charlotte Dravet in 1978 (1). She reported the condition to be severe myoclonic epilepsy (SME), and it was later named after her.

How Common Is Dravet Syndrome?

Dravet syndrome is rare and estimated to have an incidence of 1 in about 15,700 cases in the United States (2).

Furthermore, about 5% of babies with DS may experience a seizure within the first 12 months, and 7% of babies may develop the symptoms by three years of age (1). The disorder usually manifests in the first year of a child’s age or is diagnosed by their preschool age.

What Does Dravet Syndrome Look Like In Babies?

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The first and most noticeable sign of Dravet syndrome in babies is epileptic seizures, involving jerking muscular movements, particularly on one side of the body. The seizures are often varied, sudden, frequent, and prolonged. High fever usually accompanies the first epileptic seizure, but subsequent episodes may occur with or without fever. Experts indicate that factors such as illness or stress may trigger seizures in babies and they are often difficult to control with medications (2) (3).

Most infants during the early years of life may appear to be growing normally after an initial seizure. However, as the frequency of seizures increases, the rate at which they learn new skills may begin to decline (4).

What Are The Symptoms Of Dravet Syndrome?

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A convulsive seizure triggered by fever, typically around five to eight months, is the most common symptom of DS. However, a baby may exhibit other symptoms, which may include (2) (3) (5):

• Anxiety
• Movement disorders
• Sensory disorders
• Repeated infections
• Behavioral or developmental delays
• Speech or language delays
• Poor coordination or balancing skills (leading to walking difficulties)
• Emotional or academic challenges
• Abnormal heart rate or body temperature
• Feeding or sleeping difficulties

The symptoms of DS may vary from one baby to another and can range from mild to severe.

What Causes Dravet Syndrome?

Mutation in the SCN1A gene, which codes for sodium channels, is the fundamental cause of Dravet syndrome.

These channels are a vital component of the cell’s membranes, and a mutation in the SCN1A gene could impact the brain and nervous system’s functioning. This genetic change is responsible for the overactivity of the neurons, which might, in turn, lead to seizures and epilepsy (6).

The genetic mutationsⁱAlterations in the genetic makeup (DNA sequence) in an organism causing the ailment typically happen spontaneously and are not passed down through successive generations. However, in rare scenarios, babies with a parent or family member with the syndrome may also obtain it (5).

Quick fact

The gene causing this syndrome follows an autosomal dominant inheritance pattern, meaning an individual only needs one copy of a gene with a disease-causing variation to acquire the condition (6).

How Is Dravet Syndrome Diagnosed?

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The diagnosis is made by a physician based on the clinical presentations of the baby’s symptoms. Some of the tests that the doctor may order include:

• Physical examination to check for baby’s developmental patterns
• Detailed inquiry about the baby’s health history and seizures (type and duration)
• Genetic testing for babies with two or more seizures within 12 months or who have a history of prolonged, myoclonic seizures (within 18 months), especially on one side of the body

Besides these, a doctor may sometimes order blood tests to determine SCN1A gene mutation. However, these tests don’t screen all the genetic mutations that cause DS and hence aren’t 100% conclusive. Also, DS doesn’t have a clear genetic cause in some cases. Hence, some additional criteria are taken into consideration to diagnose DS. These include:

• Baby developing normally before a first seizure
• Two or more seizure attacks, with or without fever, under the age of one
• Occurrence of more than one type of seizure, including hemi-clonicⁱRepeated jerking movements typically beginning from one side of the body , myoclonic, or tonic-clonic seizuresⁱSeizures involving stiff and rapidly jerking muscle contractions
• Episodes of seizures lasting for more than ten minutes
• Persisting seizures past the age of 2 (even after administering epilepsy medications)

If an infant meets most or at least four of the above criteria, they are most likely to be diagnosed with DS, even when they do not carry the SCN1A gene mutation  (2) (5).

Point to consider

Usual tests such as electroencephalography (EEG) and magnetic resonance imaging (MRI) used to diagnose DS may appear normal at first in babies, delaying the diagnosis (5).

How Is Dravet Syndrome Treated?

The treatment depends on the severity of the disease and is directed toward reducing seizures and the risks of fatal outcomes. Experts at the International Consensus Panel designed the following medications for the treatment of the syndrome (7).

• First-line of treatment: Clobazam and Valproic acid (anticonvulsant medication)
• Second-line treatment: Sitripentol and Fenfluramine (usually given in conjunction with first-line medications)
• Third-line treatment: Cannabidiol (pharmaceutical grade)
• Fourth-line treatment: Topiramate and the ketogenic diet

Note

: These medications may not be suitable for infants below two, and some antiseizure medications may worsen their symptoms. Therefore, you must discuss the best treatment plan for your baby with their pediatrician or neurologist for timely management and favorable outcomes.

Alternative treatment options include:

• Vagus nerve stimulation: An intervention usually employed when the medications fail. In this technique, a tiny device is placed near the vagus nerve in the child’s neck. It sends electrical impulses to nerves to block or prevent seizures.
• Ketogenic diet: The diet is high in fat content, moderate in protein, and low in carbohydrates. It mainly focuses on managing epilepsy in babies who have started consuming solids and is typically considered a second line of treatment when medications don’t work.
• Physical, speech, and occupational therapies: These therapies aim to enhance a child’s motor and cognitive development (3).

Quick fact

Advanced gene therapies directed toward the specific SCN1A gene mutation may help the severities associated with this syndrome. However, they are still under research (8).

What Is The Prognosis Of Dravet Syndrome?

The prognosis in most cases is unfavorable, primarily because of the drug-resistant nature of the seizures associated with the condition (1). Therefore, most babies carry complications into their childhood, including cognitive, developmental, and behavioral abnormalities (9).

Although seizures and physical difficulties (including walking patterns) may decline with age, infants with DS are at a higher risk of sudden unexpected death in epilepsy (SUDEP), albeit rarely (4) (9). Generally, the outcomes vary based on the disease severity. However, proper medication and support may often help babies progress into childhood.

Can Dravet Syndrome Be Prevented?

Although the syndrome cannot be prevented, avoiding potential triggers that prompt seizures may help manage symptoms. The possible triggers of DS include:

• Infections
• Sudden temperature changes
• Leaving a high fever untreated
• Extremely stressful situations
• Sudden and high-intensity flashing lights (photosensitivity)
• Events causing a rise in body temperature (including hot water baths and increased physical activity) (5).

What Are The Complications Of Dravet Syndrome?

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Besides causing developmental delays and cognitive impairments, DS may also lead to adverse health consequences over time, which may include:

• Constant and recurring seizures (sometimes known as status epilepticusⁱA condition in which one or multiple seizures last longer than five minutes )
• Delayed motor skill development and speech difficulties
• Nutritional insufficiency
• Delayed puberty
• Bone deformities and increased risk of fractures
• Prolonged walking difficulties
• Increased risk of mental health disorders
• Increased sensitivity to light and temperatures (10).

Infographic: What Are The Complications Of Dravet Syndrome?

Timely diagnosis and treatment initiation can help manage DS. However, sometimes, Dravet syndrome may pave the way for severe and prolonged health ailments, especially when the evaluation or treatment is delayed. The infographic below provides an overview of the possible long-term consequences of the syndrome affecting different aspects of an individual’s life.

Illustration: Momjunction Design Team

Dravet Syndrome is a rare, severe form of epilepsy that can cause life-threatening seizures. Learn more about this condition in this video.

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Dr. Anuradha BansalMD

Dr. Anuradha Bansal is a highly accomplished pediatrician and neonatologist with 13 years of professional experience. Presently, she is working as Assistant Professor in the Department of Pediatrics at PIMS Jalandhar. She has done her MBBS and MD Pediatrics at GMCH, Chandigarh.

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Vidya did her post-graduation in Biotechnology from Osmania University, Hyderabad. Her interest in scientific research and writing made her pursue a career in writing, in which she now has over five years of experience. She has done certified biotechnology-related training programs under renowned organizations such as Centre For Cellular & Molecular Biology and Department of Biotechnology.

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