Down syndrome re-framed as interferonopathy with innate immune dysregulation, offering JAK-STAT inhibition targets

Historically, Down syndrome (DS), caused by trisomy 21, has been primarily understood as a neurodevelopmental disorder. However, a growing body of evidence highlights pervasive immune dysregulation, including chronic inflammation and heightened susceptibility to autoimmunity, as a core feature. This shift in perspective addresses the gap in understanding the systemic inflammatory burden in DS, which current standard-of-care approaches largely overlook, by proposing a mechanistic link between genetic dosage and immune pathology.

This comprehensive review synthesizes recent multi-omics studies to propose a novel mechanistic framework for Down syndrome (DS) immune dysregulation. Researchers analyzed existing literature to connect specific chromosome 21 gene dosage effects to systemic immune activation, moving beyond the traditional neurodevelopmental focus. The approach involved integrating findings on interferon signaling, epigenetic modifications, and transcriptional regulation to build a cohesive model of DS pathology, identifying shared features with interferon-driven, autoinflammation-like conditions.

The review identifies several key mechanisms driving immune dysregulation in Down syndrome. Increased expression of interferon receptors, encoded on chromosome 21, significantly lowers the threshold for interferon signaling, leading to persistent activation of interferon-stimulated genes (ISGs). Simultaneously, a reduction in METTL3-dependent m6A modification is proposed to stabilize pro-inflammatory transcripts, thereby enhancing innate immune sensing.

These changes are accompanied by significant chromatin accessibility remodeling, particularly enriched for AP-1-associated elements, which creates a transcriptionally primed state that amplifies inflammatory gene expression. This intricate interplay forms a feed-forward network involving interferon signaling, transcriptional activation, and cytokine production, providing a robust basis for the basal inflammatory state observed in DS and its associated high burden of immune-mediated comorbidities.