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Alternating Hemiplegia of Childhood

What is alternating hemiplegia of childhood?

Alternating hemiplegia of childhood is a rare, neurological condition that is characterized by episodes of paralysis that often impact just one side of the body and cognitive problems. It affects one in a million people, and symptoms typically appear before a child has reached 18 months of age. 

What are the symptoms of alternating hemiplegia of childhood?

Symptoms include:

  • Episodes of temporary paralysis
    • Can last anywhere from minutes to days
    • Can be triggered by the cold, extreme fatigue, bathing, stress, etc.
  • Shortness of breath
  • Flushing or paleness
  • Uncontrollable muscle activity
  • Nystagmus
  • Dystonia
  • Choreoathetosis
  • Mild to severe cognitive issues
    • Developmental delay
    • Intellectual disability

All symptoms cease while an impacted individual is sleeping, but they return upon waking.

What causes alternating hemiplegia of childhood?

In the majority of cases, a mutated ATP1A3 gene causes this condition, but in rare cases, it is the ATP1A2 gene. Both are responsible for parts of a larger protein complex, Na+/K+ ATPase. When one of these genes is altered, the protein complex is unable to transport charged ions in and out of neurons, leading to the characteristic symptoms. 

These mutations are typically sporadic, but in rare cases, they can be passed from parent to child. When this occurs, the genes are inherited in an autosomal dominant pattern. 

How is alternating hemiplegia of childhood diagnosed?

Doctors will diagnose this condition based on a physical examination, the identification of the characteristic symptoms, patient history, and specialized testing. They will also look to see if the patient’s condition falls under seven criteria:

  1. Symptoms begin before 18 months
  2. Repetitive episodes of hemiplegia that at times impact both sides of the body
  3. Quadriplegia that appears with or without an episode
  4. Relief from symptoms when asleep
  5. Additional paroxysmal attacks
  6. Signs of developmental delay or neurological abnormalities
  7. No other cause explains the symptoms

Tests are mainly used to exclude other conditions. Doctors may utilize MRI, MRS, MRA, EEG, studies of cerebrospinal fluid (CSF), and molecular genetic testing. 

What are the treatments for alternating hemiplegia of childhood?

There is no cure or treatment specific to this condition. A team of specialists will work to address the specific symptoms presented in each case. 

Where can I find out more about alternating hemiplegia of childhood?

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