Exploring the utility of whole‐exome sequencing as a diagnostic tool in a child with atypical episodic muscle weakness

The advent of whole‐exome next‐generation sequencing (WES) has been pivotal for the molecular characterization of Mendelian disease; however, the clinical applicability of WES has remained relatively unexplored. We describe our exploration of WES as a diagnostic tool in a 3½‐year old female patient with a 2‐year history of episodic muscle weakness and paroxysmal dystonia who presented following a previous extensive but unrevealing diagnostic work‐up. WES was performed on the proband and her two parents. Parental exome data was used to filter potential de novo genomic events in the proband and suspected variants were confirmed using di‐deoxy sequencing. WES revealed a de novo non‐synonymous mutation in exon 21 of the calcium channel gene CACNA1S that has been previously reported in a single patient as a rare cause of atypical hypokalemic periodic paralysis. This was unexpected, as the proband's original differential diagnosis had included hypokalemic periodic paralysis, but clinical and laboratory features were equivocal, and standard clinical molecular testing for hypokalemic periodic paralysis and related disorders was negative. This report highlights the potential diagnostic utility of WES in clinical practice, with implications for the approach to similar diagnostic dilemmas in the future.     

Retroviral-mediated gene transfer corrects very-long-chain fatty acid metabolism in adrenoleukodystrophy fibroblasts.

Adrenoleukodystrophy (ALD), a lethal demyelinating disease of the brain, is caused by mutations of a gene encoding an ATP-binding transporter, called ALDP, localized in the peroxisomal membrane. It is associated with a defective oxidation of very-long-chain fatty acids, leading to their accumulation in many tissues. This study reports that the retroviral-mediated transfer of the ALD cDNA restored very-long-chain fatty acid oxidation in ALD fibroblasts in vitro following abundant expression and appropriate targeting of the vector-encoded ALDP in peroxisomes. The same method may be used in hematopoietic cells as a further step of a gene therapy approach of ALD.     

Electrophysiologic effects of anterior septal arterial occlusion

The effect of reduction in anterior septal arterial flow on the conduction system was studied in seven anesthetized dogs. After 2 hours of occlusion P-Q, A-H and H-V intervals as well as atrioventricular nodal effective and functional refractory periods were significantly prolonged, sinoatrial conduction time was prolonged and the heart rate was decreased. The duration of the His bundle electrogram was significantly prolonged and the configuration altered. However, QRS duration did not prolong significantly. Fifteen minutes after reperfusion, A-H interval, duration of the His bundle electrogram, effective refractory period and functional refractory period returned toward control values. However, the H-V and QRS intervals as well as sinoatrial conduction time were unchanged after reperfusion. Thus, reduction of anterior septal arterial flow influences not only the distal but also the proximal portion of the conduction system; the most vulnerable part is probably the His bundle. The distal portion of the conduction system is directly influenced by ischemia itself, whereas the proximal portion is influenced through other mechanisms induced by reduction of anterior septal arterial flow.     

Utility of the Rey-15 Recognition Trial to Detect Invalid Performance in a Forensic Neuropsychological Sample

The current study sought to address the utility of the Rey Fifteen Item Test (Rey-15), with the use of a combined score [recall correct + (recognition correct – false positives)], to distinguish between valid and invalid performance among a sample of litigating persons referred for neuropsychological evaluation. Scores on the Rey-15 were analyzed across four comparison groups: (1) litigating persons with evidence of invalid performance (n = 29), (2) litigating persons with valid performance (n = 63), (3) learning-disabled patients (n = 36), and (4) a mixed clinical neuropsychological sample not involved in litigation (n = 54). A Rey-15 combined cutoff score of < 21 yielded the highest sensitivity (70%) and specificity (92.8%) rates. If the Rey-15 is to be used in clinical practice to detect invalid performance, the recognition trial with combined score < 21 should be used. Findings support the use of the combined Rey-15 score in place of the previously used recall Rey-15 score to improve sensitivity and specificity rates for detection of invalid performance in litigating neuropsychological referrals.     

Spontaneous atrial fibrillation initiated by tyramine in canine atria with increased sympathetic nerve sprouting

Sympathetic Activation and Atrial Fibrillation. Background: Chronic left ventricular myocardial infarction (LVMI) promotes atrial and pulmonary veins (PV) sympathetic nerve sprouting. Objectives: To test the hypothesis that sympathetic stimulation with tyramine initiates atrial fibrillation (AF) by early afterdepolarization (EAD)‐mediated triggered activity at the left atrial PV (LAPV) junction. Methods: LVMI was created in 6 dogs and 6 dogs served as controls. Six to 8 weeks later the activation pattern of the isolated LAPV was optically mapped using dual voltage and intracellular Ca⁺² (Ca_i²⁺)‐sensitive epifluorescent dyes before and after tyramine (5 μM) perfusion. Results: Tyramine initiated spontaneous AF in 5 of 6 atria but none in the control group (P < 0.01). The AF was initiated by late phase 3 EAD‐mediated triggered activity that arose from the LAPV junction causing functional conduction block in LA, reentry, and AF. The AF was subsequently maintained by mixed reentrant and focal mechanisms. The EADs arose during the late phase 3, when the Ca_i²⁺ level was 64 ± 12% of the peak systolic Ca_i²⁺ transient amplitude, a property caused by tyramine's simultaneous shortening of the action potential duration and lengthening of the Ca_i²⁺ transient duration in the LVMI group but not in the control. Tyrosine hydroxylase and growth associated protein 43 positive nerve sprouts were significantly increased in the sinus node, LAA, and the LSPV in the LVMI group compared to control (P < 0.01). Conclusions: Increased atrial sympathetic nerve sprouts after LVMI makes the LAPV junction susceptible to late phase 3 EAD‐mediated triggered and AF during sympathetic stimulation with tyramine.     

Oncological,functional and perioperative outcomes in transplant patients after radical prostatectomy

Purpose

Oncological surgery in immunosuppressed patients with solid organ transplantation (Tx) is challenging. These patients are thought to have higher postoperative morbidity and an increased rate of tumour progression. The aim of the present study was to analyse oncological, functional and perioperative outcomes in Tx patients following radical prostatectomy (RP).

Materials and methods

Between 1996 and 2014, 30 patients diagnosed with prostate cancer underwent RP at our institution following Tx (kidney: n = 20, heart: n = 5, liver: n = 5). Functional, oncological and perioperative follow-ups were analysed. Postoperative complications were assessed using the Clavien–Dindo classification.

Results

Median follow-up was 45 months. Median PSA was 5.3 ng/ml. Intraoperative blood loss was 600 ml at a median operating time of 180 min. Surgery in kidney Tx patients was technically feasible. Major complications occurred in 3 patients (ureteral injury, lymphocele and haematoma). Histological evaluation revealed n = 18 ≤pT2 tumours (60.0 %), n = 7 pT3a tumours (23.3 %) and n = 5 ≥pT3b tumours (16.7 %). Continence rate 12 months after surgery, defined as no or one safety pad use, was 73.3 %, while 93.3 % of the patients used ≤2 pads/24 h. After the median follow-up of 45 months, BCR-free survival was 69.0 %. In recurrent men, there was suspicion of metastasis in one patient. No cancer-specific death was observed. Five-year overall survival was 94.4 %.

Conclusion

The complication rate in patients with solid organ transplantation after RP was low. While histopathological evaluation revealed disease characteristics comparable to non-transplant patients from current RP series, postoperative continence was worse. Immunosuppressive therapy does not seem to lead to an increased rate of tumour progression.

     

BDNF tagging polymorphisms and haplotype analysis in sporadic Parkinson's disease in diverse ethnic groups

Experimental and clinical data suggest that genetic variations in brain-derived neurotrophic factor (BDNF) gene may affect risk for Parkinson's disease (PD). We performed a case-control association analysis of BDNF in three independent Caucasian cohorts (Greek, North American, and Finnish) of PD using eight tagging SNPs and five constructed haplotypes. No statistically significant differences in genotype and allele frequencies were found between cases and controls in all series. A relatively rare BDNF haplotype showed a trend towards association in the Greek (p=0.02) and the Finnish (p=0.03) series (this haplotype was not detected in the North American series). However, given the large number of comparisons these associations are considered non-significant. In conclusion, our results do not provide statistically significant evidence that common genetic variability in BDNF would associate with the risk for PD in the Caucasian populations studied here.     

Iron dysregulation in Alzheimer's disease: multimodal brain permeable iron chelating drugs, possessing neuroprotective-neurorescue and amyloid precursor protein-processing regulatory activities as therapeutic agents

Considering the multi-etiological character of Alzheimer's disease (AD), the current pharmacological approaches using drugs oriented towards a single molecular target possess limited ability to modify the course of the disease and thus, offer a partial benefit to the patient. In line with this concept, novel strategies include the use of a cocktail of several drugs and/or the development of a single molecule, possessing two or more active neuroprotective-neurorescue moieties that simultaneously manipulate multiple targets involved in AD pathology. A consistent observation in AD is a dysregulation of metal ions (Fe²⁺, Cu²⁺ and Zn²⁺) homeostasis and consequential induction of oxidative stress, associated with beta-amyloid aggregation and neurite plaque formation. In particular, iron has been demonstrated to modulate the Alzheimer's amyloid precursor holo-protein expression by a pathway similar to that of ferritin L-and H-mRNA translation through iron-responsive elements in their 5′UTRs. This review will discuss two separate scenarios concerning multiple therapy targets in AD, sharing in common the implementation of iron chelation activity: (i) novel multimodal brain-permeable iron chelating drugs, possessing neuroprotective-neurorescue and amyloid precursor protein-processing regulatory activities; (ii) natural plant polyphenols (flavonoids), such as green tea epigallocatechin gallate (EGCG) and curcumin, reported to have access to the brain and to possess multifunctional activities, such as metal chelation-radical scavenging, anti-inflammation and neuroprotection.