The infero-apical left ventricular aneurysm and long QT syndrome caused by mutation delKKP 1504–1506 in SCN5A gene

Q: What is the clinical evidence from this study?

Study design: Case Report. Population: Long QT syndrome type 3 (n=4). Intervention: SCN5A mutation delKKP 1504-1506. Primary outcome: Phenotypic expression.

Q: What does this research mean for the field?

The novel delKKP 1504-1506 mutation in the SCN5A gene is associated with prolonged QTc, infero-apical left ventricular aneurysms, and J-wave syndromes. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

Zhijuan Lu; Jiadong Lin; Yi Chen; Xiuli Zhou; Liping Lin; Xiaocong Zhang; Qiang Wang; Xinsheng Huang

doi:10.1186/s12920-026-02428-0

July 15, 2026BMC Medical GenomicsOpen Access

The infero-apical left ventricular aneurysm and long QT syndrome caused by mutation delKKP 1504–1506 in SCN5A gene

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Key result

Novel SCN5A delKKP mutation is linked to prolonged QTc, LV aneurysms, and J-wave syndromes.

n=4

Why the study?

Although myocardial functional alterations can occur in LQT3, whether a specific phenotype-genotype relationship exists remains unclear.

Key Points

To describe the clinical phenotype and genotype of long QT syndrome type 3 associated with a novel delKKP 1504–1506 mutation in the SCN5A gene within a Chinese family.
Evaluated four members across two generations of a Chinese family after a 14-year-old female presented with loss of consciousness and Mobitz type II atrioventricular block.
Conducted genetic sequencing of exon 26 of the SCN5A gene to identify the underlying pathogenic deletion.
Identified a heterozygous deletion of nine base pairs (c.4510_4518del, p.Lys1504_Lys1505_Pro1506del) in SCN5A in three family members (proband, father, and brother).
Prolonged QTc was documented in all three mutation carriers (subject II-2: 623 ms, subject II-1: 553 ms, subject I-1: 536 ms), compared to a normal QTc of 427 ms in the non-carrier mother.
All three carriers exhibited infero-apical left ventricular aneurysms with wall thinning down to 1–2 mm and akinesis, measuring 26 mm × 16 mm in the father, 16 mm × 9 mm in the brother, and 16 mm × 11 mm in the proband.

Study Design

Type

Case Report (n=4)

Multicenter

No

Structured PICO

P

Population

Four members of a Chinese family, including a 14-year-old female proband, were investigated for a novel SCN5A mutation.

The novel delKKP 1504-1506 mutation in SCN5A is associated with a complex phenotype including long QT syndrome, conduction block, J-waves, and infero-apical left ventricular aneurysms.

Limitations

The genotype and phenotype were analyzed in only four family members across two generations.
Due to the unavailability of medical records for other family members, the data are insufficient for statistical analysis.
Detailed electrophysiological, functional, and biochemical assays were not performed.
Our study did not include cardiac magnetic resonance imaging (cMRI).
A pharmacological challenge (e.g., ajmaline test) was not performed in subjects presenting with J-waves.
Given the small number of affected family members (n=3), we cannot establish a causative relationship between the delKKP 1504-1506 mutation and left ventricular aneurysms.
Genotype and phenotype analyzed in only four family members across two generations
Insufficient data for statistical analysis
Detailed electrophysiological, functional, and biochemical assays not performed
Cardiac magnetic resonance imaging (cMRI) not performed
Pharmacological challenge not performed in subjects presenting with J-waves

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Implication

Novel SCN5A mutation links LQT3 with aneurysms and J-waves; extends spectrum but hypothesis-generating and should not change practice.

Abstract

Long QT syndrome (LQTS) is considered a primary cardiac ion channelopathy. Several studies have shown that myocardial functional alterations may occur in patients with LQTS type 3 (LQT3). However, it is currently unclear whether there is a specific relationship between phenotype and genotype. The aim of this study is to provide additional information on the phenotype and genotype of LQT3 caused by a novel delKKP 1504–1506 mutation in a Chinese family. The family came to our attention because of a sustained corrected QT interval (QTc) prolongation in a 14-year-old girl who had experienced a loss of consciousness with Mobitz type II atrioventricular block one year earlier. Three family members carrying the delKKP 1504–1506 mutation demonstrated a combination of infero-apical left ventricular aneurysms and prolonged QTc, and two members showed J-waves in the right precordial lead V2. This case suggests that the delKKP 1504–1506 mutation in SCN5A may not only lead to impaired impulse propagation in the conduction system and a prolonged QTc, but may also be associated with infero-apical ventricular aneurysms and J-wave syndromes, possibly corresponding to regional myocardial fibrosis.

Discussion

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Cite This Study

Lu et al. (2026) conducted a case report in Long QT syndrome type 3 (n=4). SCN5A mutation delKKP 1504-1506 was evaluated on Phenotypic expression. The novel delKKP 1504-1506 mutation in the SCN5A gene was associated with prolonged QTc, infero-apical left ventricular aneurysms, and J-wave syndromes in three affected family members.

synapsesocial.com/papers/6a59c6b8a58755010b471c98 https://doi.org/10.1186/s12920-026-02428-0

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The infero-apical left ventricular aneurysm and long QT syndrome caused by mutation delKKP 1504–1506 in SCN5A gene

Key Points

Study Design

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

The infero-apical left ventricular aneurysm and long QT syndrome caused by mutation delKKP 1504–1506 in SCN5A gene

Key Points

Study Design

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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