Loss of one TBX5 copy disrupts 3D genome folding in heart cells, study finds

Researchers have published findings showing that loss of a single functional copy of the transcription factor gene TBX5 — a known cause of congenital heart disease — is sufficient to disrupt the three-dimensional folding of DNA inside heart cells. The work, reported via ScienceDaily, describes TBX5 as acting like an architectural organiser for chromatin: when one copy is absent, the carefully structured genomic topology that coordinates heart-development genes collapses in ways that vary from cell to cell.

The cell-to-cell variability in chromatin disruption observed in the study may help to explain a long-standing clinical puzzle: why individuals carrying the same TBX5 heterozygous mutation can present with markedly different cardiac defects, ranging from atrial septal defects to more complex structural abnormalities. The research suggests that stochastic variation in 3D genome organisation, rather than differences in the coding sequence itself, may be a significant contributor to this variable expressivity.

The authors also propose that a similar chromatin-architecture mechanism could underlie other congenital birth defects where dosage-sensitive transcription factors are involved, making TBX5 a model for understanding how single gene-copy losses propagate through genomic structure to produce diverse developmental outcomes.

The original source does not name the publishing journal or lead institution in the lede text available; readers should consult the primary paper for full methodological detail. The work is relevant to researchers studying cardiac development and chromatin biology, to genetic counsellors working with families affected by hereditary congenital heart disease, and to clinicians seeking mechanistic explanations for variable expressivity.