Dravet Syndrome Explained: From Seizures to Support

What is Dravet Syndrome?

Dravet Syndrome, a rare, severe epilepsy that originates in infancy and is commonly connected to genetic abnormalities, causes drug-resistant seizures and developmental impairments.

Definition: Dravet Syndrome, formerly SMEI, is a developmental and epileptic encephalopathy. It resists normal treatments, making it one of the hardest childhood epilepsies.

It affects approximately 1 in 15,700 people, making it a rare condition.

Genetic Basis: Mutations in the SCN1A gene, which encodes a brain signalling sodium channel, cause most cases.

Symptoms

• Seizures: Usually start between 6-12 months of age, often due to fever.
• Greater than 5 minutes (status epilepticus risk).
• Tonic-clonic, myoclonic, absence, and focal seizures.

Impact on Development:

• Delays in speech, language, and motor skills.
• Poor balance, coordination, and walking.
• Behavioral issues include hyperactivity or autism.
• Sleep difficulties, sudden unexpected death in epilepsy (SUDEP), and temperature sensitivity are other issues.

Management & Treatment

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• Seizures often resist typical anti-seizure medicines. Valproate, clobazam, stiripentol, CBD, and fenfluramine are options.
• Avoiding drugs: Sodium channel blockers like carbamazepine and lamotrigine exacerbate seizures.
• Assistance: Physical, verbal, and behavioural therapy.
• Rescue drugs for protracted seizures.

Prognosis: 

• Lifelong condition with increasing symptoms.
• While seizures may reduce with age, developmental and cognitive problems remain.
• Early diagnosis and customised treatment can increase life expectancy.

Who is affected by Dravet Syndrome?

Most typically caused by SCN1A gene abnormalities, Dravet Syndrome affects newborns and young children between 6–12 months.

Those Affected

• Seizures usually start in the first year of life due to fever or illness.
• Genetics: Mutations in the SCN1A gene affect brain sodium channel function in 80–90% of patients.
• Most SCN1A mutations are de novo (new mutations), not inherited.
• Dravet Syndrome affects boys and girls equally.
• It is rare, occurring in 1 in 15,700–40,000 live births.

Possible Risks

• Family history: Epilepsy or SCN1A mutation in a parent may raise risk; however, most instances are spontaneous.
• Fever sensitivity: Dravet Syndrome children are susceptible to fever, heat, and vaccination-induced seizures.
• Uncertain environmental cause: Not connected to lifestyle, diet, or prenatal exposures.

Causes of Dravet Syndrome?

A genetic mutation, usually in the SCN1A gene, affects the function of sodium channels in the brain and causes aberrant electrical signalling in Dravet Syndrome.

A genetic cause

• The SCN1A gene mutation is seen in 70-90% of cases.
• This gene produces a sodium channel protein needed for neuronal signalling.
• Mutations damage inhibitory neurons, increasing brain excitability and seizure risk.
• Mutations in genes, including SCN2A, SCN1B, GABRA1, STXBP1, and PCDH19 are less prevalent and have been associated with Dravet Syndrome.
• These genes regulate neuronal signalling and synaptic function.

Mutations Lead to Symptoms

• Sodium channel disruptions: Impair neuron firing.
• Imbalance of excitation and inhibition: Causes brain hyperexcitability and seizures.
• Development: Abnormal signalling causes cognitive delays, motor issues, and behavioural issues.

Family Lineage

• Most de novo mutations: Most SCN1A mutations are spontaneous.
• Rare familial cases: Rarely, mutations are passed down in families.

Nongenetic Factors

• No environmental cause: Dravet Syndrome is unrelated to nutrition, lifestyle, pregnancy, or infections.
• Triggers vs. causes Although fever, vaccines, and heat can cause seizures, they do not cause the condition.

Diagnostics of Dravet Syndrome

Dravet Syndrome is diagnosed by clinical observation, genetic testing, and exclusion of other epilepsy causes.

• To diagnose, review the clinical history and seizure pattern.
• Beginning of seizures at 6–12 months, often caused by fever.
• Seizures last longer than 5 minutes and resist typical anti-seizure drugs.
• Generalised tonic-clonic, myoclonic, and focal seizures.

Neurological and Developmental Signs

• Slow motor, verbal, and cognitive development.
• Gait and coordination issues.
• Behavioral issues (hyperactivity, autism).The 

Genetic Testing

• SCN1A gene mutation occurs in 70–90% of cases.
• Other rare gene mutations (SCN2A, SCN1B, GABRA1, STXBP1, PCDH19) may be involved.
• Genetic confirmation is the diagnostic gold standard.

The EEG

• Early EEG may look normal.
• Polyspike or spike-and-wave activity appears later in the EEG.
• MRI is often normal in early stages.
• Rule out brain structural problems.
• Not including other epilepsies
• Unlike febrile seizures, Lennox-Gastaut syndrome, and other epileptic encephalopathies.

Key Diagnostic Criteria

• Early-onset protracted febrile seizures.
• Multiple seizure kinds.
• Regression or delayed development.
• SCN1A mutation confirmed.

Dravet syndrome complications

Dravet Syndrome causes life-threatening seizures (status epilepticus), developmental delays, behavioural issues, and a higher risk of sudden unexpected death in epilepsy.

Major seizure complications

• Status Epilepticus (SE): Seizures lasting over 5 minutes or repeated without recovery.
• Common in Dravet Syndrome and a medical emergency.

Acute Encephalopathy (AE): Severe brain impairment from persistent seizures.

• It can cause permanent neurological damage.
• Sudden Unexpected Epilepsy Death (SUDEP):
• Accounts for ~50% of Dravet patient mortality.
• Around 73% of SUDEP cases occur before age 11.

Cognitive and developmental issues

• Learning issues: Progressive cognitive impairment, especially following seizures.
• Language and speech delays: Communication issues require therapy.
• Motor problems: Deficient coordination, balance, and gait
• Behaviour: Hyperactivity, autism-like traits, and sleep abnormalities.

Medical and Physical Problems

• Frequent infections: Fever and illness often cause seizures.
• Seizures can result from fever or heat.
• The adverse effects of medication Anti-seizure medicines often induce drowsiness, hunger changes, and behavioral difficulties.
• Orthopedic concerns: Chronic gait disorders might cause musculoskeletal issues.

Mental Health Issues

• Stress: Frequent emergencies and developmental delays strain families.
• Many children need physical, occupational, and speech therapy.
• Social isolation: Limited resources may challenge families.

Can Dravet Syndrome be prevented?

Due to spontaneous (de novo) genetic changes, most typically in the SCN1A gene, Dravet Syndrome cannot be prevented.

• Prevention is not possible due to genetic origin.
• New mutations are responsible for most cases.
• Lifestyle, diet, and pregnancy do not cause the syndrome because these mutations arise randomly throughout early development.

Environmentally without cause:

• Infections, poisons, and maternal health problems do not cause Dravet Syndrome.
• Not avoidable by vaccines or drugs:
• Vaccinations and fevers can produce seizures in Dravet Syndrome children, but they do not cause the disorder.

Also, read https://www.dovemed.com/diseases-conditions/dravet-syndrome.

What Families Can

Although the syndrome cannot be prevented, comorbidities and seizure triggers can be addressed to improve quality of life:

• Genetic testing promptly diagnoses Dravet Syndrome, enabling customized treatment.
• Not taking seizure-inducing drugs: Avoid sodium channel blockers including carbamazepine, lamotrigine, and phenytoin.
• Management of fever: Early antipyretic medication and monitoring can lower seizure risk.
• Temperature safety: Stay cool, avoid hot baths, and limit sun exposure.
• Emergency preparedness: Teach caregivers to utilize rescue drugs during extended seizures.
• Multidisciplinary support: Physical, linguistic, and behavioral therapies address developmental issues.

Conclusion

Most SCN1A gene mutations cause Dravet Syndrome, a rare, severe, lifelong epileptic condition that occurs in infancy. It causes chronic, drug-resistant seizures, developmental delays, and many cognitive, behavioral, and physical health issues.

Dravet Syndrome is a complex neurological disorder that requires lifelong awareness, caregiver preparedness, and holistic support. While it cannot be prevented, education, awareness, and targeted care measures help families and physicians improve outcomes and quality of life for affected children.