What is Dravet Syndrome

TL;DR: Dravet Syndrome is a rare, severe, and lifelong form of epilepsy that typically begins in the first year of life with prolonged, fever-related seizures. It is primarily caused by genetic mutations that affect how the brain’s nerve cells send electrical signals, leading to developmental delays and complex health challenges that require specialized, multidisciplinary care.

What exactly is Dravet Syndrome?

Dravet Syndrome, formerly known as Severe Myoclonic Epilepsy of Infancy (SMEI), is a complex genetic epilepsy syndrome. It is classified as a developmental and epileptic encephalopathy, meaning that the seizures themselves, along with the underlying genetic mutation, contribute to cognitive and behavioral challenges. Individuals living with Dravet Syndrome often experience a variety of seizure types, including tonic-clonic, myoclonic (muscle jerks), and focal seizures, which are frequently triggered by increases in body temperature, such as fever or warm environments.

What causes Dravet Syndrome and how does it affect the body?

The primary cause of Dravet Syndrome is a mutation in the SCN1A gene in approximately 80% to 85% of cases. This gene provides instructions for making a sodium channel protein in the brain, which is essential for the proper transmission of electrical impulses between neurons. When this gene is mutated, the brain's excitability is disrupted, leading to the characteristic seizure activity. Beyond epilepsy, the condition affects multiple body systems, often resulting in:

• Neurological and developmental impact: Most children experience some degree of developmental delay or intellectual disability.


• Motor coordination issues: Many patients struggle with gait disturbances, balance, and muscle tone (hypotonia).


• Autonomic dysfunction: This can lead to difficulties with temperature regulation, sleep patterns, and digestive health.


• Behavioral health: Features of autism spectrum disorder, hyperactivity, and social anxiety are frequently observed in the Dravet Syndrome community.

How common is Dravet Syndrome and who is affected?

Dravet Syndrome is a rare condition, with an estimated prevalence ranging from 1 in 15,000 to 1 in 40,000 individuals worldwide. It affects both males and females, with no clear geographic bias. While the mutation can be inherited from a parent, in the vast majority of cases, the SCN1A mutation occurs as a "de novo" event, meaning it is a new genetic change in the child that was not present in either parent. Currently, 453 people with Dravet Syndrome have joined the DiseaseMaps.org community to share their experiences and support one another.

What makes Dravet Syndrome unique compared to other epilepsies?

Unlike many other forms of epilepsy that may be outgrown, Dravet Syndrome is a lifelong diagnosis. It is distinguished from other childhood epilepsies by the following clinical markers:

1. Early onset: Seizures typically begin before the age of 12 months in previously healthy infants.


2. Trigger sensitivity: Seizures are uniquely sensitive to temperature, including fevers, warm baths, or even physical exertion.


3. Resistance to medication: Standard anti-seizure medications often fail to control symptoms, and some common drugs can actually worsen seizures in Dravet Syndrome patients.


4. EEG patterns: While early EEGs may appear normal, the clinical presentation remains distinct and evolves over time.

Next steps

• Consult with a pediatric neurologist or an epileptologist who specializes in genetic epilepsy syndromes.


• Ensure your child undergoes genetic testing to confirm an SCN1A mutation, which can guide treatment choices.


• Connect with the 453 members of the DiseaseMaps.org Dravet Syndrome community to share resources and lived experiences.


• Review potential treatment options with your medical team, including specialized medications or ketogenic dietary therapies.

Medical disclaimer: This information is for educational purposes only and does not constitute medical advice, diagnosis, or treatment; always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Dravet Syndrome Overview.


• Orphanet: Rare Disease Database (ORPHA: 33076).


• OMIM (Online Mendelian Inheritance in Man): #607208 (Dravet Syndrome).


• Dravet Syndrome Foundation: Clinical Guidelines and Patient Resources.