Alternating Hemiplegia of Childhood
New alternating hemiplegia of childhood research, summarized each month in plain language.
2026 so far: In January 2026 to September 2026, work on recognizing AHC/ATP1A3 disorders and tracking symptoms moved forward, while treatment evidence stayed limited to mixed routine-care reports and small series on fever-triggered episodes. Read the 2026 review
We also cover clinical trials.
Yearly update
2026 so far
- Everyday medication results. Reports described different responses from person to person, without controlled evidence of benefit.
- Fever-triggered episodes. Small reports again pointed to illness and fever as major triggers.
- Course and risks. Larger cohorts connected early course and epilepsy with outcomes.
- Recognizing AHC. Studies highlighted overlap and severe presentations that can resemble other diseases.
- Mechanism studies. Lab and imaging studies suggested mechanisms that could be tested, without showing clinical effects.
New
September 2026
- Severe early episodes. Early AHC episodes can look like brain inflammation.
- Symptom rating scale. A new AHC scale gave similar scores across clinicians.
- Score agreement. Scale scores roughly matched other movement and disability ratings.
August 2026
- Changes with age. Most worsening was in early childhood, then often steadier after 5.
- Epilepsy and outcomes. Epilepsy was linked to higher disability and SUDEP risk.
- Medicine reports. Everyday-care reports were mixed and did not prove what works.
July 2026
- Whole-brain connections. Whole-brain connections looked less efficient in AHC.
- Many brain areas. Differences showed up across many brain regions, not one spot.
- Symptom links. Connectivity measures matched movement severity and thinking test scores.
May 2026
- Fever and infection triggers. Fevers and infections were often linked to sudden neurologic worsening episodes.
- Routine test limits. Brain MRI and EEG results were often not specific enough to explain the episodes.
- Worm model nerve signaling. In worm models with AHC-like ATP1A3 changes, nerve-to-muscle signaling was disrupted.
- Other genes can look similar. One AHC-like case was linked to a RHOBTB2 gene change rather than ATP1A3.
April 2026
- Higher calcium in lab heart cells. In patient-derived heart-like cells, the ATP1A3 D801N variant was linked to higher calcium levels inside the cells.
- Shorter electrical signals. In the same lab model, each beat’s electrical signal was shorter than typical.
- NCX1 changed the signals. Blocking the calcium transporter NCX1 made the lab electrical signals look more typical.
March 2026
- Diagnosis labels often overlap. In one study, many people with ATP1A3 variants did not fit a single classic ATP1A3 diagnosis label.
- Ongoing movement symptoms. Long-lasting movement symptoms were commonly reported in addition to episodic attacks.
- Episodes were frequent. Sudden episodes such as weakness, abnormal eye movements, and spells were common.
- Same variant, different symptoms. The same ATP1A3 variant could be linked to different symptom patterns in different people.
January 2026
- Guillain-Barre look-alikes. Some ATP1A3 attacks looked like Guillain-Barre syndrome episodes.
- Fever-related triggers. Fever with infection was linked to sudden neurologic worsening.
- Mixed episode features. Movement symptoms occurred along with reduced reflexes during episodes.
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