April 2026 Research Update

At a glance

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.

Lab finding, real-life link unclear

These results suggest a possible heart-cell pathway for one variant, but it is still unclear how well this matches what happens in people with AHC.

Overview

This month, the research update was mainly about heart-cell biology in alternating hemiplegia of childhood (AHC), not about testing treatments in people.

In lab-grown heart-like cells made from a patient, one AHC-causing ATP1A3 change called D801N was linked to higher calcium levels inside the cells. Calcium helps control how heart cells signal and contract. In these models, the higher calcium levels went along with shorter electrical signals for each beat.

The same model systems also had abnormal extra electrical events. In theory, changes like this could relate to irregular heartbeats. This work does not show that irregular heartbeats happen in daily life for people with AHC. It adds a specific clue about one possible mechanism researchers can study further.

The study also pointed to a calcium transporter called NCX1 as part of the explanation. When the researchers blocked NCX1 in lab experiments, the electrical signals looked more typical and the abnormal extra events were reduced. This does not show a helpful medicine for AHC. It mainly helps narrow down which heart-related pathways and measurements might be most useful to study next.

Research topics this month

Limitations

• The evidence came from patient-derived cells and computer models, not from people in daily life.
• Only one AHC-causing ATP1A3 variant (D801N) was examined, so it may not apply to other variants.
• NCX1 blocking improved lab measurements, but this does not show benefit or safety in people with AHC.

Important information

• This document summarizes recent research from PubMed-indexed publications using automated methods.
• It is intended for educational purposes and does not replace medical advice.
• Links to the original studies are provided via PubMed, where readers can explore abstracts and, when available, access full-text articles.
• Some studies may include additional details that were not accessible for this summary.
• Readers seeking more complete detail or context may find it helpful to review the original studies directly.

1. 1.Bidzimou MK, Muralidharan P, Zhang Z, Raza D, Needs D, Sun B, Perelli RM, Moya-Mendez ME, Manivannan PKR, Hunanyan AS, Helfer A, Simmons CQ, George AL, Bers DM, Bursac N, Mikati MA, Landstrom AP. D801N in ATP1A3-encoded Na/K-ATPase alpha 3 causes cardiac arrhythmogenesis through sodium-calcium exchanger-mediated calcium overload. JCI Insight (2026). Open in new tab