Wolff-Parkinson-White syndrome: De novo variants and evidence for mutational burden in genes associated with atrial fibrillation.

BACKGROUND: Wolff-Parkinson-White (WPW) syndrome is a relatively common arrhythmia affecting ~1-3/1,000 individuals. Mutations in PRKAG2 have been described in rare patients in association with cardiomyopathy. However, the genetic basis of WPW in individuals with a structurally normal heart remains poorly understood. Sudden death due to atrial fibrillation (AF) can also occur in these individuals. Several studies have indicated that despite ablation of an accessory pathway, the risk of AF remains high in patients compared to general population. METHODS: We applied exome sequencing in 305 subjects, including 65 trios, 80 singletons, and 6 multiple affected families. We used de novo analysis, candidate gene approach, and burden testing to explore the genetic contributions to WPW. RESULTS: A heterozygous deleterious variant in PRKAG2 was identified in one subject, accounting for 0.6% (1/151) of the genetic basis of WPW in this study. Another individual with WPW and left ventricular hypertrophy carried a known pathogenic variant in MYH7. We found rare de novo variants in genes associated with arrhythmia and cardiomyopathy (ANK2, NEBL, PITX2, and PRDM16) in this cohort. There was an increased burden of rare deleterious variants (MAF ≤ 0.005) with CADD score ≥ 25 in genes linked to AF in cases compared to controls (P = .0023). CONCLUSIONS: Our findings show an increased burden of rare deleterious variants in genes linked to AF in WPW syndrome, suggesting that genetic factors that determine the development of accessory pathways may be linked to an increased susceptibility of atrial muscle to AF in a subset of patients.

The Effect of Comprehensive Medical Care on the Long-Term Outcomes of Children Discharged from the NICU with Tracheostomy.

BACKGROUND: Survival of infants with complex care has led to a growing population of technology-dependent children. Medical technology introduces additional complexity to patient care. Outcomes after NICU discharge comparing Usual Care (UC) with Comprehensive Care (CC) remain elusive. OBJECTIVE: To compare the outcomes of technology-dependent infants discharged from NICU with tracheostomy following UC versus CC. METHODS: A single site retrospective study evaluated forty-three (N=43) technology-dependent infants discharged from NICU with tracheostomy over 5½ years (2011-2017). CC provided 24-hour accessible healthcare-providers using an enhanced medical home. Mortality, total hospital admissions, 30-days readmission rate, time-to-mechanical ventilation liberation, and time-to-decannulation were compared between groups. RESULTS: CC group showed significantly lower mortality (3.4%) versus UC (35.7%), RR, 0.09 [95%CI, 0.12-0.75], P=0.025. CC reduced total hospital admissions to 78 per 100 child-years versus 162 for UC; RR, 0.48 [95% CI, 0.25-0.93], P=0.03. The 30-day readmission rate was 21% compared to 36% in UC; RR, 0.58 [95% CI, 0.21-1.58], P=0.29). In competing-risk regression analysis (treating death as a competing-risk), hazard of having mechanical ventilation removal in CC was two times higher than UC; SHR, 2.19 [95% CI, 0.70-6.84]. There was no difference in time-to-decannulation between groups; SHR, 1.09 [95% CI, 0.37-3.15]. CONCLUSION: CC significantly decreased mortality, total number of hospital admissions and length of time-to-mechanical ventilation liberation.

Rare DNA copy number variants in cardiovascular malformations with extracardiac abnormalities.

Clinically significant cardiovascular malformations (CVMs) occur in 5-8 per 1000 live births. Recurrent copy number variations (CNVs) are among the known causes of syndromic CVMs, accounting for an important fraction of cases. We hypothesized that many additional rare CNVs also cause CVMs and can be detected in patients with CVMs plus extracardiac anomalies (ECAs). Through a genome-wide survey of 203 subjects with CVMs and ECAs, we identified 55 CNVs >50 kb in length that were not present in children without known cardiovascular defects (n=872). Sixteen unique CNVs overlapping these variants were found in an independent CVM plus ECA cohort (n=511), which were not observed in 2011 controls. The study identified 12/16 (75%) novel loci including non-recurrent de novo 16q24.3 loss (4/714) and de novo 2q31.3q32.1 loss encompassing PPP1R1C and PDE1A (2/714). The study also narrowed critical intervals in three well-recognized genomic disorders of CVM, such as the cat-eye syndrome region on 22q11.1, 8p23.1 loss encompassing GATA4 and SOX7 and 17p13.3-p13.2 loss. An analysis of protein-interaction databases shows that the rare inherited and de novo CNVs detected in the combined cohort are enriched for genes encoding proteins that are direct or indirect partners of proteins known to be required for normal cardiac development. Our findings implicate rare variants such as 16q24.3 loss and 2q31.3-q32.1 loss, and delineate regions within previously reported structural variants known to cause CVMs.