Key result
Synonymous LMNA variant linked to progressive conduction disease and severe LVEF decline over 13 years.
Why the study?
Lamin A/C (LMNA) cardiomyopathy often presents with early arrhythmias, conduction disease, and a left-ventricular non-compaction phenotype, and synonymous LMNA variants can be pathogenic when they alter splicing.
Case Report (n=1)
This case report demonstrates that a splice-altering synonymous LMNA variant (c.1146C>T) can drive an arrhythmia-led cardiolaminopathy with left ventricular non-compaction and progressive systolic decline, supporting early gene-informed device therapy.
May inform LMNA risk stratification in non-compaction; extends splice-variant evidence but leaves open prospective validation.
Background Lamin A/C (LMNA) cardiomyopathy often presents with early arrhythmias and conduction disease and may express a left-ventricular non-compaction (LVNC) phenotype. Synonymous LMNA variants can be pathogenic when they alter splicing. Case summary Thirteen years ago, a 41-year-old woman presented with recurrent atrial fibrillation (AF) and underwent successful catheter ablation. Initial ECG showed first-degree atrioventricular block (PR 350–380 ms) with frequent premature ventricular complexes; echocardiography demonstrated normal chamber size and LVEF 55%. During follow-up, cardiac MRI confirmed LVNC (Petersen NC/C > 2.3). Genetic testing identified LMNA c.1146C>T (p.Gly382=), a splice-altering synonymous variant that activates a cryptic donor at the 3′ end of exon 6, deleting 13 nucleotides and causing a frameshift with a premature stop, consistent with loss-of-function. An ICD was implanted for primary prevention based on the LMNA-risk ventricular tachyarrhythmia calculation. The subsequent course included progressive conduction disease (PR to 550 ms with intermittent second-degree block), high ventricular ectopy with non-sustained VT, and LVEF decline to 30-35%. Later, AF and atypical atrial tachycardia recurred and were managed with device reprogramming and medical therapy. Due to widening QRS (≈140 ms) and high right ventricular pacing burden, the system was upgraded to CRT-D. Ongoing management focuses on rhythm control and guideline-directed heart-failure therapy. Discussion This case illustrates arrhythmia-led cardiolaminopathy with LVNC morphology and systolic decline associated with a splice-altering synonymous LMNA variant. Gene-specific risk features (variant type, atrioventricular block, non-sustained VT) supported early device therapy beyond EF-only thresholds. Integration of genotype, imaging, and arrhythmic/conduction findings enabled timely, gene-informed care over long-term follow-up.
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Husser et al. (2026) conducted a case report in Lamin A/C (LMNA) cardiomyopathy with left ventricular non-compaction (LVNC) (n=1). Splice-altering synonymous LMNA c.1146C>T (p.Gly382=) variant was evaluated on Clinical progression of conduction disease, ventricular ectopy, and left ventricular systolic function. The splice-altering synonymous LMNA c.1146C>T variant was associated with LVNC, PR prolongation to 550 ms, non-sustained VT, and LVEF decline from 55% to 30-35% over 13 years, requiring CRT-D upgrade.
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