Can Dravet syndrome (Severe Myoclonic Epilepsy of Infancy) present with normal developmental milestones initially?

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From the Guidelines

Dravet syndrome can present with normal developmental milestones initially, but this is often followed by developmental delays and cognitive impairment after seizure onset. According to the study published in Genetics in Medicine 1, the diagnosis and management of Dravet syndrome are crucial in minimizing seizures and potentially reducing developmental impacts. The study highlights the importance of comprehensive treatment, including medications such as stiripentol, clobazam, valproate, or cannabidiol.

Some key points to consider in the diagnosis and management of Dravet syndrome include:

  • Early diagnosis is critical in minimizing seizures and reducing developmental impacts
  • Comprehensive treatment with medications can help control seizures and potentially reduce developmental delays
  • The severity of developmental impairment varies among individuals, with some experiencing mild cognitive delays while others develop more severe intellectual disability
  • The developmental impact is related to the underlying genetic mutation, the frequency and severity of seizures, and how well seizures are controlled with medication

It is essential to note that while development may appear normal in early infancy before seizures begin, developmental stagnation or regression commonly occurs as the condition progresses. The neurological basis for these developmental issues stems from the abnormal sodium channel function that affects normal brain development and neuronal communication. As stated in the study 1, the involvement of healthcare professionals, including specialized nurses, speech-language therapists, physiotherapists, occupational therapists, pedagogics, and education experts, is crucial in providing comprehensive care for individuals with Dravet syndrome.

From the Research

Presentation of Dravet Syndrome

  • Dravet syndrome, also known as Severe Myoclonic Epilepsy of Infancy, is a debilitating epileptic encephalopathy of childhood 2.
  • The syndrome typically manifests with febrile status epilepticus and progresses to a multifocal epilepsy with febrile and non-febrile seizures with encephalopathy 3.
  • Early development in infancy is often normal, but signs of regression appear in the second year of life and are often accompanied by convulsive status epilepticus, alternating hemiconvulsions, and myoclonic seizures 4.

Developmental Milestones

  • Early normal development in infancy evolves into moderate to severe intellectual impairment, motor impairment, behavioral abnormalities, and later a characteristic crouching gait 5.
  • Patients with Dravet syndrome may present with normal developmental milestones initially, but later develop signs of regression and intellectual disability 4.
  • The normal development in early infancy can make it challenging to suspect the diagnosis of Dravet syndrome, and the correct diagnosis is often delayed 4.

Diagnosis and Treatment

  • Diagnosis of Dravet syndrome can be confirmed by genetic testing that shows mutations within the SCN1A gene 4.
  • Treatment of Dravet syndrome typically involves a combination of anticonvulsants, and the goal is to balance reduction of seizure burden with adverse effects of therapies 6.
  • Several agents, including clobazam, valproate, levetiracetam, topiramate, and stiripentol, have been shown to be effective in managing seizures in Dravet syndrome, but even with polytherapy, only a small percentage of patients achieve adequate seizure control 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Dravet Syndrome: A Review of Current Management.

Pediatric neurology, 2020

Research

Pharmacotherapy for Dravet Syndrome.

Paediatric drugs, 2016

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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