Dravet Syndrome and SCN1A

By Dovy Paukstys, Founder, Komori Care

This article is educational and is not medical advice. It does not diagnose, treat, prevent, or cure any condition. Komori is not a medical device, is not FDA-cleared, does not detect seizures, and is not intended for people with epilepsy. Talk with a neurologist or epileptologist about personal medical decisions. Households living with epilepsy should use clinically validated seizure-detection devices as directed by their care team.

Dravet is not "bad baby seizures." It's a specific syndrome. Families hear the name and then get a gene report they can't read. That's a rotten way to learn a rare disease.

I don't have Dravet. Nobody in my house does. I opened the NINDS Dravet page and the GeneReviews chapter on SCN1A seizure disorders. Those are the sources. This is a map, not a treatment plan.

What it is

NINDS: Dravet syndrome is an epilepsy that begins in infancy or early childhood. It belongs to the developmental and epileptic encephalopathies. DEE. Drug-resistant seizures plus significant developmental delay.

GeneReviews puts Dravet at the severe end of an SCN1A spectrum. The mild end is things like simple febrile seizures and GEFS+. Same gene family, very different lives. Phenotype can vary even inside one family.

Older name: severe myoclonic epilepsy in infancy (SMEI). GeneReviews prefers Dravet because some kids who otherwise fit never have myoclonus.

How it shows up

NINDS: seizures start in infancy, typically between 6 and 12 months. Different types, but most kids have tonic-clonic seizures. Some have hemi-clonic seizures (jerking on one half of the body). Fevers often ride along. Seizures change over time and are often hard to treat. Status epilepticus (continuous seizure, emergency) can happen a lot, especially before age five.

GeneReviews (citing Wirrell 2017 clinical criteria): presentation between 1 and 18 months after a stretch of normal development. Seizures often prolonged. Recurrent generalized tonic-clonic or hemiconvulsive. Myoclonic seizures typically by age two. Other types after that. Triggers they list: hyperthermia (hot bath, exertion, fever after vaccination), light stimuli, or sodium channel-blocking antiseizure medicine. Status is common. Medicines are hard. Seizures often ease after puberty. They rarely vanish.

Those two ranges (6 to 12 months vs 1 to 18 months) are not a fight. Infancy. A clinician dates onset from the chart.

NINDS also lists what can pile on later. Prolonged and frequent seizures. Developmental delay and intellectual disability. Autism. Behavior problems. Movement and balance issues. Sleep trouble. Growth and nutrition problems. Sensory processing issues. Autonomic problems (breathing, heartbeat, blood pressure).

GeneReviews adds crouched gait as kids get older, ataxia, inattention, impulsivity. Some degree of cognitive impairment is always seen in the Dravet phenotype they describe, moderate to severe.

SCN1A, in human words

NINDS: most people with Dravet have a de novo (new) change in SCN1A. Not inherited. Happened on its own.

SCN1A helps make sodium ion channels. Those channels move sodium into brain cells and help the cell fire. A change can unbalance electrical activity and cause seizures.

Rarely the variant is inherited. Autosomal dominant. A parent might be mildly affected, maybe febrile seizures without the cognitive picture. Sometimes mosaicism: some of the parent's cells have the variant, some don't. Mild or no symptoms in the parent, a more affected child.

Most people with Dravet have disease-causing SCN1A variants. A few other genes can look similar. NINDS names PCDH19-related epilepsy as one lookalike, mostly in girls.

GeneReviews: diagnosis of an SCN1A seizure disorder is established by finding a heterozygous pathogenic variant. For the Dravet phenotype, published figures for an identified SCN1A variant sit in a wide range (they table 33% to 90% depending on the series). Sequence testing catches most. Some are deletions a simple sequence test misses. A negative test does not automatically kill a clinical Dravet diagnosis.

NINDS agrees. A variant supports the diagnosis. If they don't find one, the doctor may still diagnose Dravet from the symptoms. Early diagnosis helps kids get the right care. A genetic counselor explains the test.

GeneReviews cites population estimates for Dravet around 1 in 15,000 (Wu 2015) and nearby numbers from Denmark and the UK. Rare. Not imaginary.

Diagnosis is clinical, then genetic

NINDS: physical exam, symptoms, history. EEG and MRI may be suggested. Those are often normal when seizures first appear. Then genetic testing if Dravet is on the table.

GeneReviews: early EEGs often normal or nonspecific. Later, generalized spike-and-wave, polyspike-and-wave, multifocal spikes. MRI typically normal or mild atrophy / hippocampal sclerosis.

A pediatric epileptologist should be in this, not a message-board vote. Vaccine-proximate first seizures show up in the SCN1A literature GeneReviews summarizes. That does not mean "the vaccine caused Dravet." It means fever after a shot can unmask a syndrome that was already in the gene. GeneReviews notes immunization does not appear to change the course, and authors have argued not to alter the schedule without a neurologist.

Treatment belongs with a specialist

I will not write doses. I will not pick a best drug.

NINDS: lifelong condition. Main goal is reduce or stop seizures, which helps prevent status epilepticus and SUDEP. Seizures are often hard to control. They name medicines used in Dravet (valproic acid, clobazam, topiramate, stiripentol) and note FDA has approved fenfluramine and cannabidiol for seizures in Dravet. They also name medicines that may make seizures worse: oxcarbazepine, carbamazepine, phenytoin, lamotrigine.

GeneReviews is in the same neighborhood. Care is best from a physician familiar with this pharmacotherapy. They also flag sodium-channel blockers as agents that can worsen seizures in this spectrum.

That's why random "try carbamazepine" advice is dangerous here. The same drug class that helps other epilepsies can punch this one.

NINDS: ketogenic diet is also used and can be effective in Dravet. Physical, occupational, and speech therapy for the rest of the picture. Watch gait in later childhood. "Crouch gait" is a thing they want families and clinicians looking for.

Gene-based therapy trials are underway, NINDS says. Research, not a clinic default.

What this page will not do

No parent testimonial. No ranking. No "we use X at home." No consumer monitor as a Dravet plan.

SUDEP risk is part of the serious DEE conversation. The AAN/AES SUDEP counseling still lands on seizure control under a clinician. I wrote that explainer separately. A gadget does not prevent SUDEP. Komori is not a medical device, does not detect seizures, is not intended for people with epilepsy.

If this sounds like your child, you want a pediatric epileptologist and a genetics consult. Dravet Syndrome Foundation is the patient-group NINDS lists. I'm a blog, not a center.

FAQ

What gene is tied to most Dravet cases?

SCN1A. NINDS: most people have a de novo change in that sodium-channel gene. A few cases look similar with other genes, including PCDH19.

Does a negative genetic test rule Dravet out?

No. NINDS: doctors may still diagnose Dravet from symptoms if they don't find a variant. GeneReviews: diagnosis of the syndrome is clinical, and some SCN1A changes are deletions a basic sequence test misses.

When do seizures start?

NINDS: typically 6 to 12 months. GeneReviews clinical criteria: 1 to 18 months after normal development. Infancy. Prolonged, often fever-related at the start.

Can this page tell us which medicine to use?

No. NINDS names medicines commonly used and names some that may worsen seizures. Choice and amounts are a specialist's job. No doses here.

Sources

• NINDS, Dravet Syndrome: https://www.ninds.nih.gov/health-information/disorders/dravet-syndrome
• GeneReviews, SCN1A Seizure Disorders (Miller and Sotero de Menezes, last revision Feb 17, 2022): https://www.ncbi.nlm.nih.gov/books/NBK1318/
• NINDS, Epilepsy and Seizures: https://www.ninds.nih.gov/health-information/disorders/epilepsy-and-seizures