Dravet syndrome key facts

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Dravet syndrome: a rare and severe type of epilepsy¹,²

A lifelong condition with significant impact on quality of life (QoL) for patients and families3-5
Usually starts in childhood
Can affect development
Doesn’t respond well to treatment (treatment-resistant)
There is no cure for Dravet syndrome⁶

Incidence reported to be: 1 in 15,700 – 1 in 40,900⁷,⁸.
Involves multiple types of seizures.⁹
Genetic testing can help confirm diagnosis¹⁰.
~85% of children diagnosed with Dravet syndrome carry a mutation to a gene, known as SCN1A³.
5-10% cases are inherited. 90-95% cases are completely random.^11–15
Diagnosis is based on clinical evaluation¹⁶.
A rare disease that can be misdiagnosed for other epilepsies or go undiagnosed¹⁷.
4-20% mortality rate by adulthood.^18,19

The most common seizure types are:^3,20-25

Generalised tonic-clonic – Begins with stiffness in the arms and legs, followed by jerky movements in the arms, legs, and head with a loss of consciousness
Myoclonic – Involuntary, brief, jerk-like movements that cause a sudden muscle contraction
Hemiclonic – Affects only one side of the body
Tonic – Stiffness in the arms and legs
Clonic – Jerky movements in the arms, legs, and head
Tonic-atonic – Muscles in the body become stiff and then relax
Focal with clearly observable motor signs – Affects a limited area of the brain and the affected person remains conscious

There are four stages of Dravet syndrome:

Febrile stage (infancy):²⁶ High probability of diagnosis within the first year, characterised by long-lasting seizures related to fever, often requiring emergency treatment.
Worsening stage (1-5 years):^{26, 27} Motor seizures become more common, triggered by environmental factors, other seizure types may appear, such as myoclonic seizures or absences. Children may show lack of coordination, loss of muscle tone, and a decline in dexterity.
Stabilisation stage (around 10 years):^{26, 28} Seizures become shorter, less frequent, occurring during sleep, tonic seizures may occur, with milder forms having one episode per year. Patients develop a crouching gait, often leaning on others or using a wheelchair. Cognitive impairment is often present.
Adulthood:^{26, 28, 29}: Seizures persist, mainly during sleep, with generalised tonic-clonic seizures. Progressive worsening in adulthood includes movement disorders, tremors, and symptoms akin to Parkinson’s disease. Other seizure types may diminish, but adults may face additional health problems due to Dravet syndrome. About a quarter of patients may also experience loss of bone density with an increased risk of fractures

SUDEP (sudden unexpected death in epilepsy) is a fear for parents and caregivers of people with Dravet syndrome, and the risk should be discussed with a healthcare professiona^29-31. The risk of SUDEP in children with Dravet syndrome is estimated to be 30 times greater than other childhood-onset epilepsies^{32, 33}.

Aspects of patient’s daily life affected by Dravet syndrome:³⁴

Gait disturbance – Can impact patient independence
Sleep – Sleep difficulties worsen seizures, more seizures lead to less sleep, creating a cycle
Toilet training – Late to learn, sometimes incontinent
Feeding – Feeding difficulties
School – Missed school days, require additional support

Current treatment options:

Antiseizure medications
Ketogenic diet^{16, 35, 36}
Trigger management³⁷
Vagus nerve stimulation (pacemaker-like device that sends electrical impulses to the vagus nerve in the neck)³⁸

Seizures in Dravet syndrome³⁹
Seizures can be triggered by daily occurrences³⁷: Emotional stress or excitement, sunlight, flashing lights or patterns, changes in body temperature. Begin within the first year of life, present in a developmentally normal infant, can be repetitive, can sometimes be prolonged (lasting more than 5 minutes of continuous seizure activity without recovery between seizures for tonic-clonic seizures, known as status epilepticus)⁴⁰. Seizures are not adequately controlled in 90% of peopl e with Dravet syndrome⁴¹. Other features of Dravet syndrome:³,⁴² Cognitive problems, motor and behavioural disorders increasing with age.

Impact on family and caregivers
The responsibility of care can have a significant impact on day-to-day life⁴. The lives of Dravet syndrome patients, and those of their caregivers and families, are directly and indirectly impacted by the physical and emotional demands of the disease:⁴³

66% of caregivers experience depression due to the devastating nature of Dravet syndrome²⁹
35% of adult siblings report a history of treatment for clinical depression⁴⁴
58% of siblings aged 9-12 reported feeling worried or scared when their sibling has a seizure⁴⁴
74% of caregivers report concerns about the emotional impact on siblings of children with Dravet syndrome²⁹
79% of siblings aged 9-12 feared that their siblings might die⁴⁴
81% stopped working because of their caregiving responsibilities⁴

References:

1. Campbell JD, Whittington MD, Kim CH, et al. Epilepsy Behav. 2018;80:152–6. 2. Cardenal-Muñoz E, Auvin S, Villanueva V, et al. Epilepsia Open. 2022;7(1):11–26. 3. Zuberi SM, Wirrell E, Yozawitz E, et al. Epilepsia. 2022;63(6):1349–97. 4. Lagae L, Irwin J, Gibson E, et al. Seizure. 2019;65:72– 9. 5. Wirrell EC, Hood V, Knupp KG, et al. Epilepsia. 2022;63(7):1761–77. 6. Dravet Syndrome UK. Treatments and Outcomes. www.dravet.org.uk/ about-dravet-syndrome/treatments-and-outcomes/. Accessed July 2024. 7. Wu YW, Sullivan J, McDaniel SS, et al. Pediatrics. 2015;136(5):e1310–5. 8. Brunklaus A, Ellis R, Reavey E, et al. Brain. 2012;135(Pt 8):2329–36. 9. Darra F, Battaglia D, Dravet C, et al. Epilepsia. 2019;60(S3):S49–S58. 10. Cetica V, Chiari S, Mei D, et al. Neurology. 2017;88(11):1037–44. 11. Marini C, Scheffer IE, Nabbout R, et al. Epilepsia. 2011;52(S2):24–9. 12. Claes L, Del-Favero J, Ceulemans B, et al. Am J Hum Genet. 2001;68(6):1327–32. 13. Nabbout R, Gennaro E, Dalla Bernardina B, et al. Neurology. 2003;60(12):1961–7. 14. Wallace RH, Hodgson BL, Grinton BE, et al. Neurology. 2003;61(6):765–9. 15. Fujiwara T, Sugawara T, Mazaki-Miyazaki E, et al. Brain. 2003;126 (Pt 3):531–46. 16. Figueiredo R, Rocha R, Freitas Baptista C, et al. Birth Growth MJ. 2021;30(4):213–8. 17. Gil-Nagel A, Sanchez-Carpintero R, San Antonio V, et al. Rev Neurol. 2019;68(2):75–81. 18. Cross JH, Galer BS, Gil-Nagel A, et al. Seizure. 2021;93:154–9. 19. Sullivan J, Benítez A, Roth J, et al. Epilepsia. 2024;65(5):1240–63. 20. Wirrell EC, Laux L, Donner E, et al. Pediatr Neurol. 2017;68:18–34.e3. 21. Epilepsy Society. Seizures An introduction to epileptic seizures. https://epilepsysociety.org.uk/sites/default/files/2023-12/SeizuresNovember2023_3.pdf. Updated Nov 2023. Accessed July 2024. 22. Edwards JC. CNS Spectr. 2001;6(9):750–5. 23. Fisher RS, Cross HJ, D’Souza C, et al. Epilepsia. 2017;58(4):531–42. 24. Johns Hopkins Medicine. Types of Seizures. www.hopkinsmedicine.org/health/conditions-and-diseases/epilepsy/types-of-seizures. Accessed July 2024. 25. Medlink®Neurology. Hemiclonic seizures. www.medlink.com/articles/hemiclonic-seizures. Updated Jan 2024. Accessed July 2024. 26. Gataullina S, Dulac O. Seizure. 2017;44:58–64. 27. Miller IO, Sotero de Menezes MA. SCN1A Seizure Disorders. 2007. In: Adam MP, Feldman J, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993–2024. Accessed July 2024. 28. Wyers L, Van de Walle P, Hoornweg A, et al. Eur J Paediatr Neurol. 2019;23(3):357–67. 29. Villas N, Meskis MA, Goodliffe S. Epilepsy Behav. 2017;74:81–6. 30. Jensen MP, Liljenquist KS, Bocell F, et al. Epilepsy Behav. 2017;74:135–43. 31. Skluzacek JV, Watts KP, Parsy O, et al. Epilepsia. 2011;52(S2):95–101. 32. Kalume F. Respir Physiol Neurobiol. 2013;189(2):324–8. 33. Harden C, Tomson T, Gloss D, et al. Neurology. 2017;88(17):1674–80. 34. Dravet Syndrome UK. DSUK Family Guide. www.dravet.org.uk/dsuk-family-guide/. Updated Jan 2024. Accessed July 2024. 35. Gorria Redondo N, Angulo García ML, Montesclaros Hortigüela Saeta M, et al. An Pediatr (Barc). 2016;84(6):341–3. 36. Garcia-Peñas JJ. Rev Neurol. 2018;66(S01):S71–5. 37. UCSF Benioff Children’s Hospital. Dravet syndrome. www.ucsfbenioffchildrens.org/conditions/dravet_syndrome/treatment.html. Updated Feb 2024. Accessed July 2024. 38. González HFJ, Yengo-Kahn A, Englot DJ. Neurosurg Clin N Am. 2019;30(2):219–30. 39. Dravet C. Epilepsia. 2011;52(S2):3–9. 40. Wylie T, Sandhu DS, Murr NI. Status Epilepticus. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan. Accessed July 2024. 41. Lagae L, Brambilla I, Mingorance A, et al. Dev Med Child Neurol. 2018;60(1):63–72. 42. Brunklaus A, Dorris L, Zuberi SM. Epilepsia. 2011;52(8):1476–82. 43. Whittington MD, Knupp KG, Vanderveen G, et al. Epilepsy Behav. 2018;80:109–13. 44. Bailey LD, Schwartz L, Dixon- Salazar T, et al. Epilepsy Behav. 2020;112:107377.

Dravet syndrome key facts

Dravet syndrome key facts

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