<p>Hub genes.</p>

Functional enrichment and immune infiltration analyses revealed their involvement in immune regulation and inflammatory processes. Three hub genes <i>NPPA</i>, <i>ACE</i>, and <i>POMC</i> were recognized as key molecular links between HCM and AF. Validation using the GSE36961 dataset confirmed the upregulation of <i>NPPA</i> in HCM, supporting its potential as a central gene connecting the two conditions.

Consistent with the bioinformatics findings, exploratory clinical verification findings of serum levels of N-terminal fragment of A-type natriuretic peptide (NT-proANP), encoded by <i>NPPA</i>, were markedly elevated in both the HCM and HCM with AF groups compared with healthy controls (<i>P</i> < 0.01). Moreover, NT-proANP concentrations were significantly higher in the HCM + AF group than in the HCM-only group (<i>P</i> < 0.01).</p> <p>Conclusion</p><p>This study identifies a shared genetic link between HCM and AF.

The findings strongly associate elevated NT-proANP levels, encoded by the <i>NPPA</i> gene, with AF in HCM patients. We propose NT-proANP as a promising circulating biomarker for stratifying AF risk in this patient population.</p></div>