SCN5A Mutation Type and a Genetic Risk Score Associate Variably With Brugada Syndrome Phenotype in SCN5A Families

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Brugada syndrome (BrS) is characterized by the type 1 Brugada ECG pattern. Pathogenic rare variants in SCN5A (mutations) are identified in 20% of BrS families in whom incomplete penetrance and genotype-negative phenotype-positive individuals are observed. E1784K-SCN5A is the most common SCN5A mutation identified. We determined the association of a BrS genetic risk score (BrS-GRS) and SCN5A mutation type on BrS phenotype in BrS families with SCN5A mutations.

[Pretreatment mass casualty incident workflow analysis : Comparison of two level 1 trauma centers]

BACKGROUND

Mass casualty incidents (MCI) have particularly high demands on patient care processes but occur rather rarely in daily hospital routine. Therefore, it is common to use simulations to train staff and to optimize institutional processes.

OBJECTIVES

Aim of study was to compare the pre-therapeutic in-house workflow of two differently structured level 1 trauma sites in the case of a simulated mass casualty incident (MCI).

MATERIALS AND METHODS

A MCI of 70 patients was simulated by actors in a manner that was as realistic as possible. The on-site triage assigned 7 cases to trauma site A with relatively long in-house distances and 4 patients to an independent trauma site B in which these distances were relatively short. During in-house treatment, time intervals for reaching milestones were measured and compared using the Mann-Whitney U test.

RESULTS

As no simultaneous patient arrival occurred, the Patient Distribution Matrix proved to be effective. Site A needed more time (minutes) from admission to endpoints (A: 31.85 ± 7.99; B: 21.62 ± 4.76; p = 0.059). In detail, the time intervals were particularly longer for both patient stay in trauma room (A: 8.46 ± 3.02; B: 2.73 ± 0.78, p < 0.01) and transfer time to the CT room (A: 1.81 ± 0.62; B: 0.06 ± 0.03, p < 0.01). A shorter stay in the CT room did not compensate these effects (A: 8.86 ± 1.84; B: 10.40 ± 2.89, p = 0.571). For both sites, image calculation and distribution were relatively time consuming (17.36 ± 3.05).

CONCLUSIONS

Although short in-house distances accelerated pretherapeutic treatment processes significantly, both sites remained clearly within the "golden hour". The strongest potential bottleneck was the time interval until images were available at the endpoints.

Hypomorphic PCNA mutation underlies a human DNA repair disorder

Numerous human disorders, including Cockayne syndrome, UV-sensitive syndrome, xeroderma pigmentosum, and trichothiodystrophy, result from the mutation of genes encoding molecules important for nucleotide excision repair. Here, we describe a syndrome in which the cardinal clinical features include short stature, hearing loss, premature aging, telangiectasia, neurodegeneration, and photosensitivity, resulting from a homozygous missense (p.Ser228Ile) sequence alteration of the proliferating cell nuclear antigen (PCNA). PCNA is a highly conserved sliding clamp protein essential for DNA replication and repair. Due to this fundamental role, mutations in PCNA that profoundly impair protein function would be incompatible with life. Interestingly, while the p.Ser228Ile alteration appeared to have no effect on protein levels or DNA replication, patient cells exhibited marked abnormalities in response to UV irradiation, displaying substantial reductions in both UV survival and RNA synthesis recovery. The p.Ser228Ile change also profoundly altered PCNA's interaction with Flap endonuclease 1 and DNA Ligase 1, DNA metabolism enzymes. Together, our findings detail a mutation of PCNA in humans associated with a neurodegenerative phenotype, displaying clinical and molecular features common to other DNA repair disorders, which we showed to be attributable to a hypomorphic amino acid alteration.

Characterization of early repolarization during ajmaline provocation and exercise tolerance testing

BACKGROUND

Early repolarization (ER) in the inferior electrocardiogram leads is associated with idiopathic ventricular fibrillation, but the majority of subjects with ER have a benign prognosis. At present, there are no risk stratifiers for asymptomatic ER.

OBJECTIVE

To examine the response to ajmaline provocation and exercise in potentially high-risk subjects with ER and without a definitive cardiac diagnosis.

METHODS

Electrocardiographic data were reviewed for ER at baseline and during ajmaline and exercise testing in 229 potentially high-risk patients (mean age 37.7±14.9 years; 55.9% men). ER was defined as J-point elevation in ≥2 consecutive leads and stratified by type, territory, J-point height, and ST-segment morphology.

RESULTS

Baseline ER was present in 26 (11.4%; 19 men) patients. During ajmaline provocation and exercise, there were no new ER changes. ER with rapidly ascending ST-segment and lateral ER consistently diminished. There were 7 patients with persistent ER during ajmaline and/or exercise. They were all men with inferior or inferolateral ER and horizontal/descending ST segment. Those with persistent ER during exercise were more likely to have a history of unexplained syncope than those in whom ER changes diminished (P<.01). Subtle nondiagnostic structural abnormalities were demonstrated in 3 of these patients.

CONCLUSIONS

ER with horizontal/descending ST-segment morphology in the inferior or inferolateral leads that persists during exercise is more common in patients with prior unexplained syncope and may identify patients at higher risk of arrhythmic events. ER that persists during ajmaline provocation and/or exercise may reflect underlying subtle structural abnormalities and should prompt further investigation.