A 45-year-old man with sudden cardiac death, cutaneous abnormalities and a rare desmoplakin mutation: a case report and literature review

Sinus arrest in a p.Arg160X-DSP-positive patient without evidence of desmoplakin-mediated cardiomyopathy: a case report

Background

Pathogenic/Likely pathogenic variants in DSP-encoded desmoplakin are strongly associated with arrhythmogenic cardiomyopathy (ACM). However, their contribution towards sinus node dysfunction has not been well-delineated.

Case summary

A 74-year-old man with a pathogenic variant of DSP-encoded desmoplakin (c.478C >T; p.Arg160X) but no evidence of ACM presented with one episode of syncope in the setting of a gastrointestinal illness. Workup including echocardiography, cardiac magnetic resonance imaging, and Holter monitor did not show evidence of ACM or significant arrhythmias. One month later, he experienced several closely-spaced episodes of syncope associated with long sinus pauses and sinus arrest documented on telemetry. He underwent urgent dual chamber pacemaker implantation, during which a ventricular programmed stimulation study was performed and was negative for sustained ventricular arrhythmias. His syncopal episodes resolved and he had no recurrent events on three-month follow-up.

Discussion

As highlighted here, DSP-encoded desmoplakin pathogenic/Likely pathogenic variants may contribute to isolated sinus node dysfunction. This clinical link should be further explored in larger studies involving patients with DSP variants.

Arrhythmogenic left ventricular cardiomyopathy caused by a novel likely pathogenic DSP mutation, p.K1165Rfs*8, in a family with sudden cardiac death

OBJECTIVE

We conducted an investigation into the clinical and molecular characteristics of Arrhythmogenic left ventricular cardiomyopathy (ALVC) caused by a novel likely pathogenic mutation in an Iranian pedigree with sudden cardiac death (SCD).

BACKGROUND

ALVC is a genetically inherited myocardial disease characterized by the substitution of fibro-fatty tissue in the left ventricular myocardium, predominantly inherited in an autosomal dominant pattern and is commonly associated with genes involved in encoding desmosomal proteins, specifically Desmoplakin (DSP).

METHODS

The patient and available family members underwent a comprehensive clinical assessment, including Cardiac magnetic resonance (CMR) imaging, along with Whole-exome sequencing (WES). The identified variant was confirmed and segregated by Polymerase chain reaction (PCR) and Sanger sequencing in the family members.

RESULTS

A novel likely pathogenic heterozygous variant, DSP (NM_004415.4), c.3492_3498del, p.K1165Rfs*8 was discovered in the proband. This variant is likely to be the primary reason for ALVC in this specific family. This variant was confirmed by Sanger sequencing and segregated in other affected members of the family.

CONCLUSION

We identified a novel likely pathogenic variant in the DSP gene, which has been identified as the cause of ALVC in an Iranian family. Our investigation underscores the importance of genetic testing, specifically WES, for individuals suspected of ALVC and have a family history of SCD.

Genetic Background and Clinical Features in Arrhythmogenic Left Ventricular Cardiomyopathy: A Systematic Review

In recent years a phenotypic variant of Arrhythmogenic cardiomyopathy has been described, characterized by predominant left ventricular (LV) involvement with no or minor right ventricular abnormalities, referred to as Arrhythmogenic left ventricular cardiomyopathy (ALVC). Different disease-genes have been identified in this form, such as Desmoplakin (DSP), Filamin C (FLNC), Phospholamban (PLN) and Desmin (DES). The main purpose of this critical systematic review was to assess the level of knowledge on genetic background and clinical features of ALVC. A search (updated to April 2022) was run in the PubMed, Scopus, and Web of Science electronic databases. The search terms used were “arrhythmogenic left ventricular cardiomyopathy” OR “arrhythmogenic cardiomyopathy” and “gene” OR “arrhythmogenic dysplasia” and “gene”. The most represented disease-gene turned out to be DSP, accounting for half of published cases, followed by FLNC. Overall, ECG abnormalities were reported in 58% of patients. Major ventricular arrhythmias were recorded in 26% of cases; an ICD was implanted in 29% of patients. A total of 6% of patients showed heart failure symptoms, and 15% had myocarditis-like episodes. DSP is confirmed to be the most represented disease-gene in ALVC patients. An analysis of reported clinical features of ALVC patients show an important degree of electrical instability, which frequently required an ICD implant. Moreover, myocarditis-like episodes are common.