Next-generation sequencing refines the genetic architecture of Greek GnRH-deficient patients

Isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) is a rare disease with a wide spectrum of reproductive and non-reproductive clinical characteristics. Apart from the phenotypic heterogeneity, IGD is also highly genetically heterogeneous with >35 genes implicated in the disease. Despite this genetic heterogeneity, genetic enrichment in specific subpopulations has been described. We have previously described low prevalence of genetic variation in the Greek IGD cohort discovered with utilization of Sanger sequencing in 14 known IGD genes. Here, we describe the expansion of genetic screening in the largest IGD Greek cohort that has ever been studied with the usage of whole-exome sequencing, searching for rare sequencing variants (RSVs) in 37 known IGD genes. Even though Sanger sequencing detected genetic variation in 21/81 IGD patients in 7/14 IGD genes without any evidence of oligogenicity, whole exome sequencing (WES) revealed that 27/87 IGD patients carried a rare genetic change in a total of 15 genes with 4 IGD cases being oligogenic. Our findings suggest that next-generation sequencing (NGS) techniques can discover previously undetected variation, making them the standardized method for screening patients with rare and/or more common disorders.

Unilateral renal agenesis as an early marker for genetic screening in Kallmann syndrome

Isolated GnRH Deficiency (IGD) that is either displayed as Kallmann Syndrome (KS) or normosmic idiopathic hypogonadotropic hypogonadism (nIHH) is a rare Mendelian disorder with wide clinical and genetic variability. Apart from the arrest of pubertal development, IGD is also characterized by a variety of non- reproductive features including unilateral renal agenesis (URA), midline defects, dental & ocular defects and many more. In this analysis we explored the role of unilateral renal agenesis, as a screening tool for detection of genetic changes associated with IGD. We performed detailed genetic screening with Sanger sequencing in 14 genes associated with Isolated GnRH Deficiency as well as screening of intragenic deletions in the gene of anosmin 1-ANOS1 with MLPA. No genetic variation was detected, suggestive of an alternative genetic cause for URA in these normosmic patients, highlighting the necessity of further genetic screening.

Dissemination of a theory-based online bone health program: Two intervention approaches

With the increasing nationwide emphasis on eHealth, there has been a rapid growth in the use of the Internet to deliver health promotion interventions. Although there has been a great deal of research in this field, little information is available regarding the methodologies to develop and implement effective online interventions. This article describes two social cognitive theory–based online health behavior interventions used in a large-scale dissemination study (N = 866), their implementation processes, and the lessons learned during the implementation processes. The two interventions were a short-term (8-week) intensive online Bone Power program and a longer term (12-month) Bone Power Plus program, including the Bone Power program followed by a 10-month online booster intervention (biweekly eHealth newsletters). This study used a small-group approach (32 intervention groups), and to effectively manage those groups, an eLearning management program was used as an upper layer of the Web intervention. Both interventions were implemented successfully with high retention rates (80.7% at 18 months). The theory-based approaches and the online infrastructure used in this study showed a promising potential as an effective platform for online behavior studies. Further replication studies with different samples and settings are needed to validate the utility of this intervention structure.

Comparison of resource utilization of pulmonary vein isolation: cryoablation versus RF ablation with three-dimensional mapping in the Value PVI Study

BACKGROUND

Point-to-point focal radiofrequency (RF) catheter ablation for aberrant pulmonary vein triggers that manifest into atrial fibrillation (AF) is the traditional method for treating symptomatic drug-resistant paroxysmal AF (PAF) when an ablation procedure is warranted. More recently, pulmonary vein isolation (PVI) using the cryoballoon has been demonstrated to be safe and effective (STOP AF clinical trial). Currently, two small studies have reviewed the procedural efficiency when comparing cryoballoon to focal RF catheter ablation procedures; however, no multicenter study has yet reported on this comparison of the two types of ablation catheters.

METHODS

A multicenter retrospective chart extraction and evaluation was conducted at seven geographically mixed cardiac care centers. The study examined procedural variables during ablation for PVI in PAF patients.

RESULTS

In several procedural measurements, the two modalities were comparable in efficiencies, including: acute PVI >96%; length of hospital stay at approximately 27 hours; and about 30% usage of adenosine after procedural testing. However, when compared to RF catheters, the cryoballoon procedure demonstrated a 13% reduction in laboratory occupancy time (247 min vs 283 min), a 13% reduction in procedure time (174 min vs 200 min), and a 21% reduction in fluoroscopy time (33 min vs 42 min). Additionally, when comparing the material usage of both cryoballoon and RF catheters, the cryoballoon used more radiopaque contrast agent (78 cc vs 29 cc) while using less intraprocedural saline (1234 cc vs 2386 cc), intracardiac echocardiography (88% vs 99%), three-dimensional electroanatomic mapping (30% vs 87%), and fewer transseptal punctures (1.5 vs 1.9).

CONCLUSION

This study is the first United States multicenter examination to report the procedural comparisons between the cryoballoon and focal RF catheters when used for the treatment of PAF patients. In this hospital chart review study, potential advantages were found when operating the cryoballoon with regard to hospital resource allocation. There was no statistical difference between cryoballoon and RF catheters for acute PVI success during the ablation procedure.

Functional consequences of AXL sequence variants in hypogonadotropic hypogonadism

CONTEXT

Prior studies showed that Axl /Tyro3 null mice have delayed first estrus and abnormal cyclicity due to developmental defects in GnRH neuron migration and survival.

OBJECTIVE

The objective of the study was to test whether the absence of Axl would alter reproductive function in mice and that mutations in AXL are present in patients with Kallmann syndrome (KS) or normosmic idiopathic hypogonadotropic hypogonadism (nIHH).

DESIGN AND SETTING

The sexual maturation of Axl null mice was examined. The coding region of AXL was sequenced in 104 unrelated, carefully phenotyped KS or nIHH subjects. Frequency of mutations was compared with other causes of GnRH deficiency. Functional assays were performed on the detected mutations.

RESULTS

Axl null mice demonstrated delay in first estrus and the interval between vaginal opening and first estrus. Three missense AXL mutations (p.L50F, p.S202C, and p.Q361P) and one intronic variant 6 bp upstream from the start of exon 5 (c.586-6 C>T) were identified in two KS and 2 two nIHH subjects. Comparison of the frequencies of AXL mutations with other putative causes of idiopathic hypogonadotropic hypogonadism confirmed they are rare variants. Testing of the c.586-6 C>T mutation revealed no abnormal splicing. Surface plasmon resonance analysis of the p.L50F, p.S202C, and p.Q361P mutations showed no altered Gas6 ligand binding. In contrast, GT1-7 GnRH neuronal cells expressing p.S202C or p.Q361P demonstrated defective ligand dependent receptor processing and importantly aberrant neuronal migration. In addition, the p.Q361P showed defective ligand independent chemotaxis.

CONCLUSIONS

Functional consequences of AXL sequence variants in patients with idiopathic hypogonadotropic hypogonadism support the importance of AXL and the Tyro3, Axl, Mer (TAM) family in reproductive development.

An holistic approach to turning patients

Turning patients who are immobile is usually undertaken expressly to prevent pressure sores. Here the authors highlight some of the other factors that need to be taken into account when nursing dependent and/or immobile patients.