Citations

Background: Brugada syndrome (BrS) is an oligogenic arrhythmic disease with increased risk of sudden cardiac arrest. Several BrS or ECG traits-related single-nucleotide polymorphisms (SNPs) were identified through previous genome-wide association studies in white patients. We aimed to validate these SNPs in BrS patients in the Taiwanese population, assessing the cumulative effect of risk alleles and the BrS-polygenic risk score in predicting cardiac events. Methods: We genotyped 190 unrelated BrS patients using the TWB Array, and Taiwan Biobank was used as controls. SNPs not included in the array were imputed by IMPUTE2. Cox proportional hazards model was used to evaluate the associations between each particular SNP, the collective BrS-polygenic risk score, and clinical outcomes. Results: Of the 88 previously reported SNPs, 22 were validated in Taiwanese BrS patients ( P <0.05). Of the 22 SNPs, 2 (rs10428132 and rs9388451) were linked with susceptibility to BrS, 10 were SNPs previously reaching genome-wide significance, and 10 were SNPs associated with ECG traits. For the 3 most commonly reported SNPs, disease risk increased consistently with the number of risk alleles (odds ratio, 3.54; P trend =1.38×10 −9 for 5 risk alleles versus 1). Similar patterns were observed in both SCN5A mutation+ (odds ratio, 3.66; P trend =0.049) and SCN5A mutation− (odds ratio, 3.75; P trend =8.54×10 −9 ) subgroups. Furthermore, BrS patients without SCN5A mutations had more risk alleles than BrS patients with SCN5A mutations regardless of the range of polygenic risk scores. Three SNPs (rs4687718, rs7784776, and rs2968863) showed significant associations with the composite outcome (sudden cardiac arrest plus syncope, hazard ratio, 2.13, 1.48, and 0.41; P =0.02, 0.006, and 0.008, respectively). Conclusions: Our findings suggested that some SNPs associated with BrS or ECG traits exist across multiple populations. The cumulative risk of the BrS-related SNPs is similar to that in white BrS patients, but it appears to correlate with the absence of SCN5A mutations.

Iodine is an essential component of thyroid hormones, which play a critical role in neurodevelopment. The iodine status of pregnant women and their newborns is not checked routinely. Extremely Low Gestational Age Newborns do not receive Iodine supplementation while on parenteral nutrition (PN). We measured urine iodine levels and thyroid function tests in 50 mother–infant dyads at birth, at 1 week, 1, 2, 3 months and near discharge. We correlated maternal and neonatal urine iodine levels with thyroid functions and measured iodine levels in milk and PN. In our study, 64% of mothers were iodine deficient at the time of delivery, their free T4 levels were 0.48 (0.41–0.54) ng/dL with normal thyroid-stimulating hormone (TSH). Iodine levels were thirty-fold higher in extremely low gestational age newborns (ELGAN) exposed to iodine comparing to full terms (p < 0.001), but this effect lasted <1 week. At 1 month of age, ELGAN on PN developed iodine deficiency (p = 0.017) and had high thyroglobulin levels of 187 (156–271) ng/mL. Iodine levels improved with enteral feeds by 2 months of age (p = 0.01). Iodine deficiency is prevalent among pregnant women and ELGAN; in particular, those on PN are at risk of hypothyroidism. Iodine supplementation during pregnancy and postnatally should be considered to avoid iodine deficiency.

Efficient precision genome engineering requires high frequency and specificity of integration at the genomic target site. Here, we describe a set of resources to streamline reporter gene knock-ins in zebrafish and demonstrate the broader utility of the method in mammalian cells. Our approach uses short homology of 24–48 bp to drive targeted integration of DNA reporter cassettes by homology-mediated end joining (HMEJ) at high frequency at a double strand break in the targeted gene. Our vector series, pGTag (plasmids for Gene Tagging), contains reporters flanked by a universal CRISPR sgRNA sequence which enables in vivo liberation of the homology arms. We observed high rates of germline transmission (22–100%) for targeted knock-ins at eight zebrafish loci and efficient integration at safe harbor loci in porcine and human cells. Our system provides a straightforward and cost-effective approach for high efficiency gene targeting applications in CRISPR and TALEN compatible systems.