Use of hierarchical models to analyze European trends in congenital anomaly prevalence

Causes of death in individuals with trisomy 18 after the first year of life

Mortality in individuals with trisomy 18 has significantly decreased over the past 20 years, but there is scant literature addressing the prognosis and cause of death in individuals with trisomy 18 and survival past the first year of life (YOL). This study analyzed factors associated with mortality and cause of death in a retrospective cohort of 174 individuals with trisomy 18 and survival past the first YOL, the largest such series to date. Data were collected via retrospective survey of parents of affected individuals. Prenatal diagnosis of trisomy 18; postnatal respiratory distress; maternal age > 35 years; birthweight <2000 g; brain and spinal cord defect(s); atrial and/or ventricular septal defect(s); inability to feed orally without medical assistance; and failure to meet sitting and rolling milestones were associated with mortality in this sample. Cause of death was compared between our cohort of individuals with trisomy 18 and existing literature on those with mortality before the first YOL. Individuals with trisomy 18 with mortality after the first YOL demonstrated a predominance of infectious (n = 10/22) and postoperative (n = 6/22) contributing causes of death, in contrast to the existing literature, which shows a predominance of cardiopulmonary causes of death (e.g., cardiopulmonary arrest, pulmonary hypertension). These findings demonstrate that individuals with trisomy 18 and survival past the first YOL have unique medical needs, but further research is needed to develop clinical guidelines for this growing population.

Rho kinase-dependent apical constriction counteracts M-phase apical expansion to enable mouse neural tube closure

Cellular generation of mechanical forces required to close the presumptive spinal neural tube, the 'posterior neuropore' (PNP), involves interkinetic nuclear migration (INM) and apical constriction. Both processes change the apical surface area of neuroepithelial cells, but how they are biomechanically integrated is unknown. Rho kinase (Rock; herein referring to both ROCK1 and ROCK2) inhibition in mouse whole embryo culture progressively widens the PNP. PNP widening is not caused by increased mechanical tension opposing closure, as evidenced by diminished recoil following laser ablation. Rather, Rock inhibition diminishes neuroepithelial apical constriction, producing increased apical areas in neuroepithelial cells despite diminished tension. Neuroepithelial apices are also dynamically related to INM progression, with the smallest dimensions achieved in cells positive for the pan-M phase marker Rb phosphorylated at S780 (pRB-S780). A brief (2 h) Rock inhibition selectively increases the apical area of pRB-S780-positive cells, but not pre-anaphase cells positive for phosphorylated histone 3 (pHH3⁺). Longer inhibition (8 h, more than one cell cycle) increases apical areas in pHH3⁺ cells, suggesting cell cycle-dependent accumulation of cells with larger apical surfaces during PNP widening. Consequently, arresting cell cycle progression with hydroxyurea prevents PNP widening following Rock inhibition. Thus, Rock-dependent apical constriction compensates for the PNP-widening effects of INM to enable progression of closure.This article has an associated First Person interview with the first authors of the paper.

Trends in the Prevalences of Selected Birth Defects in Korea (2008⁻2014)

Little information is available on the prevalences of birth defects in Korea. The aims of this study were to estimate recent prevalences of selected birth defects and to analyze the prevalence trends of these defects during the period from 2008 to 2014. Prevalences were calculated for 69 major birth defects using health insurance claim data obtained from the Korea National Health Insurance Service (NHIS). Prevalence rate ratios were calculated using Poisson regression to analyze trends over the 7-year study period. The overall prevalence of a major birth defect was 446.3 per 10,000 births (95% CI: 444.0–448.6); 470.9 per 10,000 births (95% CI: 467.6–474.2) for males and 420.2 per 10,000 births (95% CI: 417–423.4) for females. The prevalence rates of the most common birth defects over the study period were; septal defect (138.2 per 10,000; 95% CI: 136.9–139.5), congenital hip dislocation (652 per 10,000; 95% CI: 64.1–65.9), and ventricular septal defect (62.62 per 10,000; 95% CI: 61.7–63.5). During the study period, a significant increase in the prevalence of a major birth defect was observed with a prevalence rate ratio (PRR) of 1.091. The strongest trend was observed for renal dysplasia, which had a PRR of 1.275 (95% CI: 1.211–1.343), and upward trends were observed for urogenital anomalies, such as, renal agenesis (PRR 1.102, 95% CI: 1.067–1.138), undescended testis (PRR 1.082, 95% CI: 1.072–1.093) and hypospadias (PRR 1.067, 95% CI: 1.044–1.090). This study shows an overall increase in the prevalences of birth defects, including hypospadias and undescended testis, which are known to be associated with endocrine factors. In the future, standardized birth defect registries should be established to enable these trends to be monitored.