CHD2 myoclonic encephalopathy
Last updated 18 Aug 2020
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CHD2 myoclonic encephalopathy is a condition characterised by recurrent seizures (epilepsy), abnormal brain function (encephalopathy), and intellectual disability. Epilepsy begins in childhood, typically between ages 6 months and 4 years. Each individual may experience a variety of seizure types. The most common are myoclonic seizures, which involve involuntary muscle twitches. Other seizure types include sudden episodes of weak muscle tone (atonic seizures); partial or complete loss of consciousness (absence seizures); seizures brought on by high body temperature (febrile seizure); or tonic-clonic seizures, which involve loss of consciousness, muscle rigidity, and convulsions. Some people with CHD2 myoclonic encephalopathy have photosensitive epilepsy, in which seizures are triggered by flashing lights. Some people with CHD2 myoclonic encephalopathy experience a type of seizure called atonic-myoclonic-absence seizure, which begins with a drop of the head, followed by loss of consciousness, then rigid movements of the arms. Epilepsy can worsen, causing prolonged episodes of seizure activity that last several minutes, known as status epilepticus. The seizures associated with CHD2 myoclonic encephalopathy are called refractory because they usually do not respond to therapy with anti-epileptic medications.
Description
CHD2 myoclonic encephalopathy is a condition characterised by recurrent seizures (epilepsy), abnormal brain function (encephalopathy), and intellectual disability. Epilepsy begins in childhood, typically between ages 6 months and 4 years. Each individual may experience a variety of seizure types. The most common are myoclonic seizures, which involve involuntary muscle twitches. Other seizure types include sudden episodes of weak muscle tone (atonic seizures); partial or complete loss of consciousness (absence seizures); seizures brought on by high body temperature (febrile seizure); or tonic-clonic seizures, which involve loss of consciousness, muscle rigidity, and convulsions. Some people with CHD2 myoclonic encephalopathy have photosensitive epilepsy, in which seizures are triggered by flashing lights. Some people with CHD2 myoclonic encephalopathy experience a type of seizure called atonic-myoclonic-absence seizure, which begins with a drop of the head, followed by loss of consciousness, then rigid movements of the arms. Epilepsy can worsen, causing prolonged episodes of seizure activity that last several minutes, known as status epilepticus. The seizures associated with CHD2 myoclonic encephalopathy are called refractory because they usually do not respond to therapy with anti-epileptic medications.
Other signs and symptoms of CHD2 myoclonic encephalopathy include intellectual disability that ranges from mild to severe and delayed development of speech. Rarely, individuals can have a loss of acquired skills (developmental regression) following the onset of epilepsy. Some people with CHD2 myoclonic encephalopathy have autism spectrum disorders, which are conditions characterised by impaired communication and social interaction. In some instances, areas with a loss of brain tissue (atrophy) have been found with medical imaging.
Inheritance patterns
The source lists the following possible inheritance patterns: Autosomal dominant. More than one pattern can apply in different cases.
Related genes
Other names
CHD2 encephalopathy
CHD2-related neurodevelopmental disorders
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Further reading and references
- CHD2 myoclonic encephalopathy; MedlinePlus, National Library of Medicine.
- Lund C, Brodtkorb E, Oye AM, Rosby O, Selmer KK. CHD2 mutations in Lennox-Gastaut syndrome. Epilepsy Behav. 2014 Apr;33:18-21. doi: 10.1016/j.yebeh.2014.02.005. Epub 2014 Mar 12.
- Suls A, Jaehn JA, Kecskes A, Weber Y, Weckhuysen S, Craiu DC, Siekierska A, Djemie T, Afrikanova T, Gormley P, von Spiczak S, Kluger G, Iliescu CM, Talvik T, Talvik I, Meral C, Caglayan HS, Giraldez BG, Serratosa J, Lemke JR, Hoffman-Zacharska D, Szczepanik E, Barisic N, Komarek V, Hjalgrim H, Moller RS, Linnankivi T, Dimova P, Striano P, Zara F, Marini C, Guerrini R, Depienne C, Baulac S, Kuhlenbaumer G, Crawford AD, Lehesjoki AE, de Witte PA, Palotie A, Lerche H, Esguerra CV, De Jonghe P, Helbig I; EuroEPINOMICS RES Consortium. De novo loss-of-function mutations in CHD2 cause a fever-sensitive myoclonic epileptic encephalopathy sharing features with Dravet syndrome. Am J Hum Genet. 2013 Nov 7;93(5):967-75. doi: 10.1016/j.ajhg.2013.09.017. Epub 2013 Oct 24.
- Thomas RH, Zhang LM, Carvill GL, Archer JS, Heavin SB, Mandelstam SA, Craiu D, Berkovic SF, Gill DS, Mefford HC, Scheffer IE; EuroEPINOMICS RES Consortium. CHD2 myoclonic encephalopathy is frequently associated with self-induced seizures. Neurology. 2015 Mar 3;84(9):951-8. doi: 10.1212/WNL.0000000000001305. Epub 2015 Feb 11.
- Trivisano M, Striano P, Sartorelli J, Giordano L, Traverso M, Accorsi P, Cappelletti S, Claps DJ, Vigevano F, Zara F, Specchio N. CHD2 mutations are a rare cause of generalized epilepsy with myoclonic-atonic seizures. Epilepsy Behav. 2015 Oct;51:53-6. doi: 10.1016/j.yebeh.2015.06.029. Epub 2015 Aug 7.
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