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Disease Profile

SCN2A related disorders

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

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ICD-10

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Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

SCN2A-related disorders; SCN2A related conditions; SCN2A-related epilepsy;

Summary

SCN2A related disorders are a group of epilepsy and neurodevelopmental disorders, each caused by changes (mutations) in a gene called SCN2A.[1] These disorders range from mild to severe and primarily include:[2]

  • Infantile epileptic encephalopathy (IEE) characterized by seizures beginning in infancy (before 12 months of age) followed by developmental delay.
  • Benign (familial) infantile seizures (BISs) characterized by seizures beginning in infancy that stop by 2 years of age, without major long-term effects.
  • Autism spectrum disorder/intellectual disability (ASD/ID) characterized by global developmental delay (particularly of social and language skills). Up to a third of children with ASD/ID may also develop seizures in childhood, around of after 12 months of age.

Signs and symptoms depend on the specific condition and severity in each person. Some children with an SCN2A related disorder do not fit directly into one of these major forms.[2] Most children with SCN2A mutations will have seizures that start in the first few weeks of life. Other symptoms of an SCN2A related disorder may include feeding or gastrointestinal problems, developmental delay, movement disorders, and/or poor muscle tone (hypotonia).[3]

SCN2A mutations may be inherited from a parent or may occur for the first time in a child with an SCN2A related disorder (a de novo mutation). Treatment depends on symptoms and severity, but often includes antiepileptic drugs (AEDs).[3] Unfortunately, in many cases, seizures associated with SCN2A related disorders cannot be controlled, even with the use of multiple AEDs. However, for infants who begin to have seizures within 3 months of birth, nonselective sodium channel blockers (such as phenytoin and carbamazepine) are more effective. Treatment for global developmental delay, ASD, and other associated signs and symptoms follow standard management recommendations.[2]

Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Social Networking Websites

      Learn more

      These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

      Where to Start

      • Unique is a source of information and support for families and individuals affected by rare chromosome disorders. Click on the link to view information about SCN2A related disorders.

        Selected Full-Text Journal Articles

          References

          1. Wolff M, Johannesen KM, Hedrich UB. Genetic and phenotypic heterogeneity suggest therapeutic implications in SCN2A-related disorders. Brain. March 4, 2017; [Epub ahead of print]:https://www.ncbi.nlm.nih.gov/pubmed/28379373.
          2. Sanders SJ, Campbell AJ, Cottrell JR, et al. Progress in Understanding and Treating SCN2A-Mediated Disorders. Trends in Neurosciences. 2018; [Epub ahead of print]:https://docs.wixstatic.com/ugd/59e4a2_b573b7558fdd4123bc9b2e10e0a3f11f.pdf.
          3. SCN2A related conditions. Unique. 2016; https://www.rarechromo.org/information/Chromosome%20%202/SCN2A%20related%20conditions%20FTNW.pdf.