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Genetic and Rare Diseases Information Center (GARD)

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Alternating hemiplegia of childhood

Other Names for this Disease
  • AHC
  • Alternating hemiplegia
  • Alternating hemiplegia syndrome
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What is alternating hemiplegia of childhood (AHC)?

What is alternating hemiplegia of childhood (AHC)?

Alternating hemiplegia of childhood (AHC) is a severe disorder affecting the neurological system of children usually 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. Symptoms disappear during sleep and return upon waking.[1] The majority of affected children display some degree of developmental delay, abnormal eye (oculomotor) movements, uncontrolled limb movements (including ataxia, dystonia, and choreoathetosis) and seizures that occur in up to 50% of patients.[1]  Treatment options are limited to therapies that can help with some of the symptoms. The majority of cases of classic AHC are caused by new mutation in the ATP1A3 gene that is not inherited.[2] Thus, most patients with AHC with a mutation in ATP1A3 gene do not have a family history of the disorder.  Additional genes such as CACNA1A and ATP1A2 have been identified in some cases of AHC with an atypical clinical presentation.  ATP1A2 mutations were shown, however, to be more consistent with familial hemiplegic migraine.[3]
Last updated: 11/29/2012

  1. Sweney M T, et al. Alternating Hemiplegia of Childhood: Early Characteristics and Evolution of a Neurodevelopmental Syndrome. Pediatrics. March 2009; 123:e534-e541.
  2. Heinzen EL, Swoboda KJ, Hitomi Y, Gurrieri F, Nicole S, de Vries B, et al. De novo mutations in ATP1A3 cause alternating hemiplegia of childhood. Nature Genetics. September 2012; 44(9):1030-4.
  3. NINDS. Alternating Hemiplegia of Childhood. September 16, 2011; Accessed 11/19/2012.