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Disease Profile

Alternating hemiplegia of childhood

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

US Estimated

Europe Estimated

Age of onset

Infancy

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ICD-10

G98

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.

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)

Alternating hemiplegia syndrome; AHC; Alternating hemiplegia

Categories

Congenital and Genetic Diseases; Nervous System Diseases

Summary

Alternating hemiplegia of childhood (AHC) is a neurological disorder that usually affects children before 18 months of age. Classic AHC causes recurrent episodes of paralysis (hemiplegia) that involve one or both sides of the body, multiple limbs, or a single limb. The paralysis may affect different parts of the body at different times and may be brief or last for several days. A characteristic feature of AHC is that symptoms disappear during sleep and return upon waking. Many affected children display some degree of developmental delay, abnormal eye (oculomotor) movements, uncontrolled limb movements (including ataxia, dystonia, and choreoathetosis) and seizures.[1][2]

The majority of cases of AHC are caused by a new change (called a mutation or pathogenic variant) in the ATP1A3 gene that is not inherited. Thus, most patients with AHC do not have a family history of the disorder. A small number of cases of AHC are caused by changes in the ATP1A2 gene.[1][2] When this condition does run in families, it follows an autosomal dominant pattern of inheritance.[2]Treatment is limited to therapies that can help reduce the severity and duration of symptoms.[1]

Symptoms

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
HPO ID
30%-79% of people have these symptoms
Bilateral tonic-clonic seizure
Grand mal seizures
0002069
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance
0000006
Choreoathetosis
0001266
Dystonia
0001332
Episodic hemiplegia
0012194
Episodic quadriplegia
0200072
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation

[ more ]

0001249
Mental deterioration
Cognitive decline
Cognitive decline, progressive
Intellectual deterioration
Progressive cognitive decline

[ more ]

0001268
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639

Diagnosis

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

    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

      • RareConnect has an online community for patients and families with this condition so they can connect with others and share their experiences living with a rare disease. The project is a joint collaboration between EURORDIS (European Rare Disease Organisation) and NORD (National Organization for Rare Disorders).

        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

          In-Depth Information

          • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
          • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
          • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
          • PubMed is a searchable database of medical literature and lists journal articles that discuss Alternating hemiplegia of childhood. Click on the link to view a sample search on this topic.

            References

            1. National Institute of Neurological Disorders and Stroke (NINDS). Alternating Hemiplegia of Childhood. March 6, 2018; https://www.ninds.nih.gov/Disorders/All-Disorders/Alternating-Hemiplegia-Information-Page.
            2. Alternating hemiplegia of childhood. Genetics Home Reference (GHR). September 2016; https://ghr.nlm.nih.gov/condition/alternating-hemiplegia-of-childhood.