Rare Truncating HAND2 Variants Predispose to Atrial Fibrillation

Q: What is the clinical evidence from this study?

Study design: Case-Control. Population: Atrial Fibrillation (n=537). Intervention: HAND2 truncating variants (Trp46 and Gln113) vs. Wild-type HAND2 (absence of variants). Primary outcome: In vitro transcriptional activation of HCN4 by Trp46-mutant HAND2 versus wild-type HAND2 (fold change) (p=0.0004).

Q: What does this research mean for the field?

Rare truncating variants in the HAND2 gene predispose to atrial fibrillation through loss of transcriptional activation of target genes HCN4 and NPPA. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

Hong Zhang; Xiao-Qing Hu; Ning Li; D Zhang; Xing‐Biao Qiu; Chenxi Yang; Ying‐Jia Xu; Yi‐Qing Yang; Yi-Xiang Wang

doi:10.3390/genes17060701

June 17, 2026GenesOpen Access

Rare Truncating HAND2 Variants Predispose to Atrial Fibrillation

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Key result

Rare truncating HAND2 variants link to atrial fibrillation via loss of HCN4 and NPPA activation.

P=0.0004
n=537

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Why the study?

Owing to substantial genetic heterogeneity, the predisposing genetic substrates for AF in most individuals remain to be ascertained.

Do rare truncating variants in the HAND2 gene predispose individuals to atrial fibrillation?

Key Points

To identify novel predisposing genetic variants responsible for familial and idiopathic atrial fibrillation and characterize their downstream molecular effects.
Enrolled a four-generation family with familial atrial fibrillation (Family-112AF, N=33), a cohort of 238 individuals with idiopathic atrial fibrillation, and 266 unrelated healthy control participants.
Conducted whole-exome sequencing and bioinformatics filtering in selected pedigree members, followed by Sanger sequencing of HAND2 across all participants.
Assessed the functional impact of identified HAND2 variants on downstream target promoters (HCN4 and NPPA) alone and with GATA4 using in vitro dual-reporter gene assays in HeLa cells.
Identified two novel heterozygous nonsense variants: NM_021973.3: c.138G>A; p.(Trp46) co-segregating with disease in Family-112AF (maximum two-point LOD score 2.6015 at θ=0.05), and NM_021973.3: c.337C>T; p.(Gln113) in one of 238 idiopathic cases, both absent in 532 control chromosomes.
In reporter assays, wild-type HAND2 transactivated HCN4 by ~15-fold versus ~1-fold for Trp46 (p=0.0004) and ~14-fold versus ~1-fold for Gln113 (p=0.0085), with co-expression showing haploinsufficiency rather than a dominant-negative effect.
Wild-type HAND2 transactivated NPPA by ~6-fold versus ~1-fold for both mutants (p=0.0004 for Trp46, p=0.0002 for Gln113), and abolished synergistic activation with GATA4 (HAND2 + GATA4 vs. Trp46 + GATA4: ~35-fold vs. ~14-fold, p=0.0007; vs. Gln113 + GATA4: ~33-fold vs. ~13-fold, p=0.0012).

Study Design

Type

Case-Control (n=537)

Multicenter

No

Structured PICO

Do rare truncating variants in the HAND2 gene predispose individuals to atrial fibrillation?

P

Population

537 Han Chinese individuals, including a 33-member pedigree with familial atrial fibrillation, 238 sporadic cases, and 266 healthy controls, were screened for rare predisposing genetic variants.

E

Exposure

Identification and functional characterization of heterozygous truncating HAND2 variations (c.138G>A [p.Trp46] and c.337C>T [p.Gln113]) using whole-exome sequencing, Sanger sequencing, and in vitro dual-reporter gene measurements.

C

Comparator

Wild-type HAND2 gene, and 266 healthy control individuals without atrial fibrillation.

O

Outcome

Identification of AF-predisposing HAND2 genetic variations and their in vitro functional effect on the transcriptional activation of AF-causative genes HCN4 and NPPA.surrogate

Main Result

Absolute Event Rate: 1% vs 15%

p-value: p=0.0004

Limitations

Functional assays were performed exclusively in HeLa cells, which lack a cardiac-specific transcriptional architecture.
The potential for nonsense-mediated mRNA decay (NMD) of the mutant HAND2 transcripts was not directly assessed in patient heart samples.
Lack of direct binding evidence (such as ChIP or EMSA) to confirm the physiological relevance of the promoter regions used in reporter assays.
Relatively modest sample size for the sporadic atrial fibrillation cohort (238 cases and 266 controls).
Age-dependent penetrance cannot be excluded
Variable expressivity cannot be excluded

Implication

Rare truncating variations in the HAND2 gene were discovered to predispose patients to atrial fibrillation, likely by impairing the transcriptional activation of key cardiac genes including HCN4 and NPPA.

Abstract

Background/Objectives: As the most prevalent supraventricular arrhythmia, affecting around 1% of people worldwide, atrial fibrillation (AF) is implicated with a multitude of detrimental clinical sequelae, encompassing congestive failure, thromboembolic cerebral stroke, and premature death. Accumulating epidemiological evidence convincingly demonstrates genetic defects as a cornerstone in the pathogenesis of idiopathic AF. Despite significant genetic underpinnings responsible for AF, owing to substantial genetic heterogeneity, the predisposing genetic substrates for AF in most individuals remain to be ascertained. Methods: A four-generation pedigree suffering from familial AF and a cohort of 238 subjects affected with idiopathic AF, together with 266 healthy people, were enrolled prospectively. Pan-exome sequencing analysis was implemented on the chosen AF pedigree members, and Sanger sequencing assay was performed on all research subjects. The functional effects of the detected HAND2 variations were examined via an in vitro dual-reporter gene measurement. Results: Two novel heterozygous truncating HAND2 variations, NM_021973.3: c.138G>A; p.(Trp46*) and NM_021973.3: c.337C>T; p.(Gln113*), were discovered in the AF pedigree and one of the 238 AF cases, respectively. The two HAND2 variants co-segregated with the AF phenotype and were absent from the 532 control chromosomes of 266 healthy individuals. Quantitative reporter gene assays unveiled that both Trp46*- and Gln113*-mutant HAND2 failed to transcriptionally activate HCN4 and NPPA, two AF-causative genes. Additionally, the two variations nullified the synergistic transcriptional activation of NPPA by HAND2 and GATA4, another recognized gene predisposing to AF. Conclusions: These findings support HAND2 as a strong candidate gene contributing to AF susceptibility, which unravels novel etiopathogenesis underpinning the occurrence and perpetuation of AF and offers a potential molecular target for individualized medicine.

Discussion

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Cite This Study

Zhang et al. (2026) conducted a case-control in Atrial Fibrillation (n=537). HAND2 truncating variants (Trp46 and Gln113) vs. Wild-type HAND2 (absence of variants) was evaluated on In vitro transcriptional activation of HCN4 by Trp46-mutant HAND2 versus wild-type HAND2 (fold change) (p=0.0004). Rare truncating HAND2 variants (Trp46 and Gln113) predispose to atrial fibrillation by failing to transcriptionally activate the AF-causative genes HCN4 and NPPA.

synapsesocial.com/papers/6a33cfcf14a9c556e66778c0 https://doi.org/10.3390/genes17060701

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Rare Truncating HAND2 Variants Predispose to Atrial Fibrillation

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Rare Truncating HAND2 Variants Predispose to Atrial Fibrillation

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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