How do I know if I have Alternating Hemiplegia Of Childhood?

Alternating Hemiplegia of Childhood (AHC) is a rare neurological disorder typically appearing before age 18 months, characterized by recurrent episodes of temporary paralysis (hemiplegia) that switch sides of the body. Diagnosis is primarily confirmed through genetic testing for mutations in the ATP1A3 gene, often following a clinical evaluation by a neurologist to distinguish these episodes from epilepsy or other movement disorders.

What are the early signs of Alternating Hemiplegia of Childhood?

The hallmark of Alternating Hemiplegia of Childhood is the onset of recurrent weakness or paralysis that affects one side of the body, then switches to the other, or affects both sides simultaneously. Early indicators often include:

• Repetitive eye movements (nystagmus) or abnormal eye deviations in early infancy.


• Episodes of dystonia (involuntary muscle contractions) or choreoathetosis (involuntary writhing movements).


• Sudden, severe episodes of hemiplegia that may last from minutes to several days.


• Symptoms often resolve during sleep and return shortly after waking.

How is a diagnosis of Alternating Hemiplegia of Childhood confirmed?

If you suspect Alternating Hemiplegia of Childhood, it is vital to keep a detailed "symptom diary" documenting the duration, triggers, and nature of the episodes. When speaking to your physician, specifically request a referral to a pediatric neurologist or a specialist in movement disorders. Ask about targeted genetic testing for the ATP1A3 gene, which is identified in approximately 75-80% of patients diagnosed with Alternating Hemiplegia of Childhood.

When should I seek urgent medical care?

While Alternating Hemiplegia of Childhood is chronic, certain scenarios require immediate emergency evaluation. Seek urgent care if the patient experiences status epilepticus, prolonged periods of respiratory distress, or if an episode of hemiplegia is accompanied by a significant change in mental status or consciousness that differs from their baseline.

How do I advocate for a diagnosis?

Because Alternating Hemiplegia of Childhood is extremely rare, many primary care providers may not be familiar with it. If your concerns are dismissed, provide your physician with literature from the NIH GARD or the Alternating Hemiplegia of Childhood Foundation. You can also connect with the 72 community members on DiseaseMaps.org who have navigated this diagnostic journey to share experiences and clinical resources.

Next steps

• Consult a pediatric neurologist specializing in movement disorders.


• Request genetic counseling and testing for the ATP1A3 gene.


• Join a patient advocacy group to connect with families who understand the nuances of this condition.


• Maintain a video log of episodes to show your medical team, as clinical descriptions are often difficult to capture accurately.

Medical disclaimer: This information is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Alternating Hemiplegia of Childhood.


• Orphanet: Alternating Hemiplegia of Childhood (ORPHA:602).


• OMIM (Online Mendelian Inheritance in Man): #104290.


• Alternating Hemiplegia of Childhood Foundation (AHCF).