Deleting a heart-rhythm and diabetes gene disrupted mitochondria and insulin signals in lab-grown human neurons

Some genes refuse to stay in one specialty. KCNQ1 encodes a potassium channel best known from cardiology — its variants cause long QT syndrome and other rhythm disorders — and from diabetes genetics, where it is a recognized type 2 diabetes susceptibility gene. It also turns up in epilepsy and psychiatric research. A study published October 13, 2026 in Communications Biology (Schall and colleagues) asked what the gene does in the developing human brain, using stem-cell-grown neurons.

How did they study a brain role for a heart gene?

The team used CRISPR to delete KCNQ1 from human induced pluripotent stem cells, then grew those cells into neural stem cells and cortical neurons. Because most disease-causing KCNQ1 variants reduce the channel's function, a deletion is a reasonable model of what those variants do. They compared the edited neurons with unedited controls from the same donor line, tracking growth, gene activity, and protein levels.

What changed without KCNQ1?

Neurons missing the gene grew their early projections — neurites, the beginnings of axons and dendrites — more slowly during the first phase of differentiation, and blocking the channel with a drug in normal cells produced a similar slowdown. Deeper profiling showed broad disruption: altered gene transcription and protein production, disturbed mitochondrial function, and disturbed insulin signaling through well-known growth pathways (including RAS/MAPK/ERK and PI3K/AKT). In other words, losing one potassium channel rippled into both the cell's energy system and one of its main metabolic control circuits.

Why does a dish of neurons matter?

People with long QT syndrome have higher rates of epilepsy, diabetes, hearing loss, and psychiatric conditions than the general population, and the overlap has never had a clean explanation. This study offers a candidate mechanism — shared disruption of insulin signaling and mitochondrial function — that could link the heart, metabolic, and brain sides of the gene's story. It is early, cell-model evidence: lab-grown neurons are not a developing child's brain, and no patient outcome has been tied to these findings yet. But it gives researchers a concrete system for testing whether protecting mitochondria or insulin signaling can offset the gene's loss.

Where the evidence stands

• Established: KCNQ1 variants cause heart-rhythm disorders including long QT syndrome, and the gene is a type 2 diabetes susceptibility gene; it also modulates insulin secretion in pancreatic beta cells.
• Preliminary: In human stem-cell-derived neurons, KCNQ1 deletion reduced early neurite outgrowth and disrupted mitochondrial function and insulin signaling (RAS/MAPK/ERK, PI3K/AKT) in transcriptome and proteome analyses.
• Absent: Evidence from patients or animal brains that these cellular changes cause symptoms, and any intervention shown to compensate for KCNQ1 loss in neurons.