Evolution of genome diagnostics in epidermolysis bullosa: Unveiling the power of next-generation sequencing.

BACKGROUND: Genome diagnostics is considered gold standard diagnostics for epidermolysis bullosa (EB), a phenotypically and genetically heterogeneous group of rare disorders characterized by blistering and wounding of mucocutaneous tissues. EB is caused by pathogenic variants in genes encoding proteins of the dermo-epidermal junction. Accurate genetic diagnosis of EB is crucial for prognostication, counselling and precision-medicine. Genome diagnostics for EB started in 1991 with the introduction of Sanger sequencing (SS), analysing one gene at a time. In 2013, SS was superseded by next-generation sequencing (NGS), that allow for high-throughput sequencing of multiple genes in parallel. Several studies have shown a beneficial role for NGS in EB diagnostics, but its true benefit has not been quantified. OBJECTIVES: To determine the benefit of NGS in EB by systematically evaluating the performance of different genome diagnostics used over time based on robust data from the Dutch EB Registry. METHODS: The diagnostic performances of SS and NGS were systematically evaluated in a retrospective observational study including all index cases with a clinical diagnosis of EB in whom genome diagnostics was performed between 01 January 1994 and 01 January 2022 (n = 308), registered at the Dutch EB Expertise Centre. RESULTS: Over time, a genetic diagnosis was made in 289/308 (94%) EB cases. The diagnostic yield increased from 89% (SS) to 95% (NGS). Most importantly, NGS significantly reduced diagnostic turnaround time (39 days vs. 211 days, p < 0.001). The likelihood of detecting variants of uncertain significance and additional findings increased from 5% and 1% (SS) to 22% and 13% (NGS) respectively. CONCLUSIONS: Our study quantifies the benefit of NGS-based methods and demonstrate they have had a major impact on EB diagnostics through an increased diagnostic yield and a dramatically decreased turnaround time (39 days). Although our diagnostic yield is high (95%), further improvement of genome diagnostics is urgently needed to provide a genetic diagnosis in all EB patients.

Surgical treatment of esophago-tracheobronchial fistulas after esophagectomy.

The aim of this study was to evaluate the surgical treatment of esophago-tracheobronchial fistulas (ETBFs) that occurred after esophagectomy with gastric conduit reconstruction in a tertiary referral center for esophageal surgery. All patients who underwent surgical repair for an ETBF after esophagectomy with gastric conduit reconstruction were included in a tertiary referral center. The primary outcome was successful recovery after surgical treatment for ETBF, defined as a patent airway at 90 days after the surgical fistula repair. Secondary outcomes were details on the clinical presentation, diagnostics, and postoperative course after fistula repair. Between 2007 and 2022, 14 patients who underwent surgical repair for an ETBF were included. Out of 14 patients, 9 had undergone esophagectomy with cervical anastomosis and 5 esophagectomy with intrathoracic anastomosis after which 13 patients had developed anastomotic leakage. Surgical treatment consisted of thoracotomy to cover the defect with a pericardial patch and intercostal flap in 11 patients, a patch without interposition of healthy tissue in 1 patient, and fistula repair via cervical incision with only a pectoral muscle flap in 2 patients. After surgical treatment, 12 patients recovered (86%). Mortality occurred in two patients (14%) due to multiple organ failure. This study evaluated the techniques and outcomes of surgical repair of ETBFs following esophagectomy with gastric conduit reconstruction in 14 patients. Treatment was successful in 12 patients (86%) and generally consisted of thoracotomy and coverage of the defect with a bovine pericardial patch followed by interposition with an intercostal muscle.

Diabetes- versus smoking-related thrombo-inflammation in peripheral artery disease.

Peripheral artery disease (PAD) is a major health problem with increased cardiovascular mortality, morbidity and disabling critical limb threatening ischemia (CLTI) and amputation. Diabetes mellitus (DM) and cigarette smoke are the main risk factors for the development of PAD. Although diabetes related PAD shows an accelerated course with worse outcome regarding complications, mortality and amputations compared with non-diabetic patients, current medical treatment does not make this distinction and includes standard antiplatelet and lipid lowering drugs for all patients with PAD. In this review we discuss the pathophysiologic mechanisms of PAD, with focus on differences in thrombo-inflammatory processes between diabetes-related and smoking-related PAD, and hypothesize on possible mechanisms for the progressive course of PAD in DM. Furthermore, we comment on current medical treatment and speculate on alternative medical drug options for patients with PAD and DM.

Occult lymph node metastases in patients without residual muscle-invasive bladder cancer at radical cystectomy with or without neoadjuvant chemotherapy: a nationwide study of 5417 patients.

PURPOSE: Little is known about the prevalence of occult lymph node metastases (LNM) in muscle-invasive bladder cancer (MIBC) patients with pathological downstaging of the primary tumor. We aimed to estimate the prevalence of occult LNM in patients without residual MIBC at radical cystectomy (RC) with or without neoadjuvant chemotherapy (NAC) or neoadjuvant radiotherapy (NAR), and to assess overall survival (OS). METHODS: Patients with cT2-T4aN0M0 urothelial MIBC who underwent RC plus pelvic lymph node dissection (PLND) with curative intent between January 1995-December 2013 (retrospective Netherlands Cancer Registry (NCR) cohort) and November 2017-October 2019 (prospective NCR-BlaZIB cohort (acronym in Dutch: BlaaskankerZorg In Beeld; in English: Insight into bladder cancer care)) were identified from the nationwide NCR. The prevalence of occult LNM was calculated and OS of patients with <(y)pT2N0 vs. <(y)pT2N+ disease was estimated by the Kaplan-Meier method. RESULTS: In total, 4657 patients from the NCR cohort and 760 patients from the NCR-BlaZIB cohort were included. Of 1374 patients downstaged to <(y)pT2, 4.3% (N = 59) had occult LNM 4.1% (N = 49) of patients with cT2-disease and 5.6% (N = 10) with cT3-4a-disease. This was 4.0% (N = 44) in patients without NAC or NAR, 4.5% (N = 10) in patients with NAC, and 13.5% (N = 5) in patients with NAR but number of patients treated with NAR and downstaged disease was small. The prevalence of <(y)pT2N+ disease was 4.2% (N = 48) in the NCR cohort and 4.6% (N = 11) in the NCR-BlaZIB cohort. For patients with <(y)pT2N+ and <(y)pT2N0, median OS was 3.5 years (95% CI 2.5-8.9) versus 12.9 years (95% CI 11.7-14.0), respectively. CONCLUSION: Occult LNM were found in 4.3% of patients with cT2-4aN0M0 MIBC with (near-) complete downstaging of the primary tumor following RC plus PLND. This was regardless of NAC or clinical T-stage. Patients with occult LNM showed considerable worse survival. These results can help in counseling patients for bladder-sparing treatments.

Extreme ultraviolet light from a tin plasma driven by a 2-µm-wavelength laser.

An experimental study of laser-produced plasmas is performed by irradiating a planar tin target by laser pulses, of 4.8 ns duration, produced from a KTP-based 2-µm-wavelength master oscillator power amplifier. Comparative spectroscopic investigations are performed for plasmas driven by 1-µm- and 2-µm-wavelength pulsed lasers, over a wide range of laser intensities spanning 0.5 - 5 × 1011 W/cm 2. Similar extreme ultraviolet (EUV) spectra in the 5.5-25.5 nm wavelength range and underlying plasma ionicities are obtained when the intensity ratio is kept fixed at I1µm/I2µm = 2.4(7). Crucially, the conversion efficiency (CE) of 2-µm-laser energy into radiation within a 2% bandwidth centered at 13.5 nm relevant for industrial applications is found to be a factor of two larger, at a 60 degree observation angle, than in the case of the denser 1-µm-laser-driven plasma. Our findings regarding the scaling of the optimum laser intensity for efficient EUV generation and CE with drive laser wavelength are extended to other laser wavelengths using available literature data.

Clinical translation and implementation of optical imaging agents for precision image-guided cancer surgery.

INTRODUCTION: The field of tumor-specific fluorescence-guided surgery has seen a significant increase in the development of novel tumor-targeted imaging agents. Studying patient benefit using intraoperative fluorescence-guided imaging for cancer surgery is the final step needed for implementation in standard treatment protocols. Translation into phase III clinical trials can be challenging and time consuming. Recent studies have helped to identify certain waypoints in this transition phase between studying imaging agent efficacy (phase I-II) and proving patient benefit (phase III). TRIAL INITIATION: Performing these trials outside centers of expertise, thus involving motivated clinicians, training them, and providing feedback on data quality, increases the translatability of imaging agents and the surgical technique. Furthermore, timely formation of a trial team which oversees the translational process is vital. They are responsible for establishing an imaging framework (camera system, imaging protocol, surgical workflow) and clinical framework (disease stage, procedure type, clinical research question) in which the trial is executed. Providing participating clinicians with well-defined protocols with the aim to answer clinically relevant research questions within the context of care is the pinnacle in gathering reliable trial data. OUTLOOK: If all these aspects are taken into consideration, tumor-specific fluorescence-guided surgery is expected be of significant value when integrated into the diagnostic work-up, surgical procedure, and follow-up of cancer patients. It is only by involving and collaborating with all stakeholders involved in this process that successful clinical translation can occur. AIM: Here, we discuss the challenges faced during this important translational phase and present potential solutions to enable final clinical translation and implementation of imaging agents for image-guided cancer surgery.

Urothelial cancer organoids: a tool for bladder cancer research.

BACKGROUND: Bladder cancer ranks among the top ten most common tumor types worldwide and represents a growing healthcare problem, accounting for a large part of total healthcare costs. Chemotherapy is effective in a subset of patients, while causing severe side effects. Tumor pathogenesis and drug resistance mechanisms are largely unknown. Precision medicine is failing in bladder cancer, as bladder tumors are genetically and molecularly very heterogeneous. Currently, therapeutic decision-making depends on assessing a single fragment of surgically acquired tumor tissue. OBJECTIVE: New preclinical model systems for bladder cancer are indispensable for developing therapeutic strategies tailored to individual patient and tumor characteristics. Organoids are small 3D tissue cultures that simulate small-size organs "in a dish" and tumoroids are a special type of cancer organoid (i.e., malignant tissue). MATERIALS AND METHODS: Since 2016, we have collaborated with the renowned Hubrecht Institute to provide proof of concept of tissue-based bladder tumoroids mimicking parental tumors. We have developed a living biobank containing bladder organoids and tumoroids grown from over 50 patient samples, which reflect crucial aspects of bladder cancer pathogenesis. RESULTS: Histological and immunofluorescence analysis indicated that the heterogeneity and subclassification of tumoroids mimicked those of corresponding parental tumor samples. Thus, urothelial tumoroids mimic crucial aspects of bladder cancer pathogenesis. CONCLUSION: Research with urothelial tumoroids will open up new avenues for bladder cancer pathogenesis and drug-resistance research as well as for precision medicine approaches.

Carcinoembryonic antigen-specific, fluorescent image-guided cytoreductive surgery with hyperthermic intraperitoneal chemotherapy for metastatic colorectal cancer.

This multicentre pilot study investigated the role of peroperative carcinoembryonic antigen (CEA)-specific fluorescence imaging during cytoreductive surgery-hyperthermic intraperitoneal chemotherapy surgery in peritoneal metastasized colorectal cancer. A correct change in peritoneal carcinomatosis index (PCI) owing to fluorescence imaging was seen in four of the 14 included patients. The use of SGM-101 in patients with peritoneally metastasized colorectal carcinoma is feasible, and allows intraoperative detection of tumour deposits and alteration of the PCI. Augmented reality guidance.

Superior efficacy of neoadjuvant chemotherapy and radical cystectomy in cT3-4aN0M0 compared to cT2N0M0 bladder cancer.

In this study, we compared complete pathological downstaging (pCD, ≤(y)pT1N0) and overall survival (OS) in patients with cT2 versus cT3-4aN0M0 UC of the bladder undergoing radical cystectomy (RC) with or without neoadjuvant chemo- (NAC) or radiotherapy (NAR). A population-based sample of 5,517 patients, who underwent upfront RC versus NAC + RC or NAR + RC for cT2-4aN0M0 UC between 1995-2013, was identified from the Netherlands Cancer Registry. Data were retrieved from individual patient files and pathology reports. pCD-rates were compared using Chi-square tests and OS was estimated by Kaplan-Meier analyses. Multivariable analyses were conducted to determine odds (OR) and hazard ratios (HR) for pCD-status and OS, respectively. We included 4,504 (82%) patients with cT2 and 1,013 (18%) with cT3-4a UC. Median follow-up was 9.2 years. In cT2 UC, pCD-rate was 25% after upfront RC versus 43% (p < 0.001) and 33% (p = 0.130) after NAC + RC and NAR + RC, respectively. In cT3-4a UC, pCD-rate was 8% after upfront RC versus 37% (p < 0.001) and 16% (p = 0.281) after NAC + RC and NAR + RC, respectively. In cT2 UC, 5-year OS was 57% and 51% for NAC + RC and upfront RC, respectively (p = 0.135), whereas in cT3-4a UC, 5-year OS was 55% for NAC + RC versus 36% for upfront RC (p < 0.001). In multivariable analysis for OS, NAC was beneficial in cT3-4a UC (HR: 0.67, 95%CI 0.51-0.89) but not in cT2 UC (HR: 0.91, 95%CI 0.72-1.15). NAR did not influence OS. In conclusion, NAC + RC was associated with superior pCD compared to RC alone and NAR + RC. Superior OS for NAC + RC compared to RC alone was especially evident in cT3-4a disease.

Treating benign ureteroenteric strictures: 27-year experience comparing endourological techniques with open surgical approach.

PURPOSE: To compare open surgical anastomotic revision with endourological techniques for the treatment of ureteroenteric strictures in patients with urinary diversions. METHODS: All records of patients treated for ureteroenteric strictures in our clinic between 1989 and 2016 were retrospectively reviewed. In 76 patients, 161 completed procedures were analyzed: 26 open revisions vs. 135 endourological treatments, including balloon dilation, Wallstent and/or laser vaporization. RESULTS: Median follow-up was 34 months. At 60 months, patency rates were 69% (95% CI 52-92%) after open vs. 27% (95% CI 19-39%) after endo-treatment (p = 0.003); median patency duration was 15.5 vs. 5 months, respectively (p = 0.014). Eventually, 15% of patients required open surgery after primary endo-treatment and 21% received endoscopic re-treatment after primary open surgery. Cox regression analysis revealed no confounding factors among the risk factors added to the model. Complication rates were higher after open surgery (27% Clavien 2, 12% Clavien 3-4 vs. 5% Clavien 1-2, 3% Clavien 3, p = 0.528). Median postoperative hospital stay was 14 days (open) vs. 2 days (endo), p < 0.001. Mean estimated glomerular filtration rate improved with + 17 (open) vs. + 8.1 (endo), p = 0.024. Renal function was compromised in 8% of patients in the open surgery group vs. 6% in the endo-treatment group. CONCLUSIONS: In these patients, in terms of patency and patency duration, open surgery was superior to endourology. Nevertheless, endourological treatments offer a safe and less-invasive alternative to delay or avoid open surgery, especially in patients who are unfit for open surgery.

Short-term outcome after cystectomy: comparison of early oral feeding in an enhanced recovery protocol and feeding using Bengmark nasojejunal tube.

PURPOSE: Cystectomy for bladder cancer is associated with a high risk of postoperative complications. Standardized perioperative protocols, such as enhanced recovery after surgery (ERAS) protocols, aim to improve postoperative outcome. Postoperative feeding strategies are an important part of these protocols. In this two-centre study, we compared complications and length of hospital stay (LOS) between an ERAS protocol with early oral nutrition and a protocol with early enteral feeding with a Bengmark nasojejunal tube. METHODS: We retrospectively reviewed 154 consecutive patients who underwent cystectomy for bladder cancer in two hospitals (Hospital A and B) between 2014 and 2016. Hospital A uses an ERAS protocol (n = 45), which encourages early introduction of an oral diet. Hospital B uses a fast-track protocol comprising feeding with a Bengmark nasojejunal tube (Bengmark-protocol, n = 109). LOS and complications according to Clavien classification were compared between protocols. RESULTS: Overall 30-day complication rates in the ERAS and Bengmark protocol were similar (64.4 and 67.0%, respectively; p = 0.463). The rate of postoperative ileus (POI) was significantly lower in the Bengmark protocol (11.9% vs. 34.4% in the ERAS protocol, p = 0.009). This association remained significant after adjustment for other variables (odds ratio 0.32, 95% confidence interval 0.11-0.96; p = 0.042). Median LOS did not differ significantly between protocols (10 days vs. 11 days in the ERAS and Bengmark protocols, respectively; p = 0.861). CONCLUSIONS: Early oral nutrition in Hospital A was well tolerated. However, the Bengmark protocol was superior with respect to occurrence of POI. A prospective study may clarify whether the lower rate of POI was due to the use of early nasojejunal tube feeding or other reasons.

Longitudinal echocardiographic and clinical follow-up of patients undergoing mitral valve surgery without concomitant tricuspid valve repair.

BACKGROUND: In patients with mild to moderate functional tricuspid regurgitation (TR) and absence of right ventricular dysfunction or tricuspid annulus (TA) dilatation, there is currently no indication for concomitant tricuspid valve (TV) repair during elective mitral valve (MV) surgery. However, long-term results are conflicting. Here, we sought to determine the clinical outcome of this cohort, the rate of TR progression after MV surgery and the role of MV aetiology. METHODS: Patients for elective MV surgery without concomitant TV repair were retrospectively analysed with longitudinal echocardiographic and clinical follow-up, focusing on TR progression and MV aetiology. Linear regression analysis was performed for change in TR at follow-up, using pre-determined variables and confounders. RESULTS: In total 204 patients without TV repair were analysed. Development of more than moderate TR after a median of 3.1 [1.6-4.6] years was rarely seen: only in 2 out of 161 patients (1.2%) with known TR grade at follow-up. Overall, median preoperative and late postoperative TR grade were equal (p = 0.116). Subanalysis showed no significant difference in MV aetiology subgroups. Preoperative TR grade and male gender were inversely correlated to change in TR. Mortality was not influenced by the 1­year postoperative TR severity. CONCLUSION: Our data showed that in a study population of patients with mild to moderate TR undergoing MV surgery without concomitant TV repair, significant late TR was rarely seen. Based on our study, it is safe to waive concomitant TV repair in this specific patient cohort.

A Multicenter Study on Long-Term Outcomes After Lung Transplantation Comparing Donation After Circulatory Death and Donation After Brain Death.

The implementation of donation after circulatory death category 3 (DCD3) was one of the attempts to reduce the gap between supply and demand of donor lungs. In the Netherlands, the total number of potential lung donors was greatly increased by the availability of DCD3 lungs in addition to the initial standard use of donation after brain death (DBD) lungs. From the three lung transplant centers in the Netherlands, 130 DCD3 recipients were one-to-one nearest neighbor propensity score matched with 130 DBD recipients. The primary end points were primary graft dysfunction (PGD), posttransplant lung function, freedom from chronic lung allograft dysfunction (CLAD), and overall survival. PGD did not differ between the groups. Posttransplant lung function was comparable after bilateral lung transplantation, but seemed worse after DCD3 single lung transplantation. The incidence of CLAD (p = 0.17) nor the freedom from CLAD (p = 0.36) nor the overall survival (p = 0.40) were significantly different between both groups. The presented multicenter results are derived from a national context where one third of the lung transplantations are performed with DCD3 lungs. We conclude that the long-term outcome after lung transplantation with DCD3 donors is similar to that of DBD donors and that DCD3 donation can substantially enlarge the donor pool.

High-energy Nd:YAG laser system with arbitrary sub-nanosecond pulse shaping capability.

We report on a laser system capable of generating high-energy (>270 mJ) temporally shaped pulses at 1064 nm with 0.43-ns shaping resolution. The pulses are generated by modulation of a continuous-wave seed laser and subsequent amplification by a dual-stage grazing-incidence Nd:YVO4 "bounce" amplifier and a Nd:YAG power amplifier (all quasi-continuous diode-pumped). The system produces pulses with a high-quality top-hat spatial beam profile with up to 0.6 GW of peak power and 44 W of average power, a power stability of 0.22% rms, and fully programmable complex temporal shapes.

Carcinoid heart disease: a guide for screening and timing of surgical intervention.

The cardiac manifestations of a neuroendocrine tumour are referred to as carcinoid heart disease (CaHD) and are associated with a poor prognosis. Surgical intervention is the only proven therapeutic option and may prolong survival and quality of life. No consensus has been reached internationally with regard to screening for CaHD and the optimal timing for surgery. Although limited evidence is available on this matter, a trend towards early surgery and subsequent reduced mortality has been observed. In this review we provide an overview of the current understanding and propose a protocol to guide cardiologists in the screening for CaHD and the timing of referral to a specialised surgical centre.

Casting wider nets for anxiety and depression: disability-driven cross-diagnostic subtypes in a large cohort.

BACKGROUND: In search of empirical classifications of depression and anxiety, most subtyping studies focus solely on symptoms and do so within a single disorder. This study aimed to identify and validate cross-diagnostic subtypes by simultaneously considering symptoms of depression and anxiety, and disability measures. METHOD: A large cohort of adults (Lifelines, n = 73 403) had a full assessment of 16 symptoms of mood and anxiety disorders, and measurement of physical, social and occupational disability. The best-fitting subtyping model was identified by comparing different hybrid mixture models with and without disability covariates on fit criteria in an independent test sample. The best model's classes were compared across a range of external variables. RESULTS: The best-fitting Mixed Measurement Item Response Theory model with disability covariates identified five classes. Accounting for disability improved differentiation between people reporting isolated non-specific symptoms ['Somatic' (13.0%), and 'Worried' (14.0%)] and psychopathological symptoms ['Subclinical' (8.8%), and 'Clinical' (3.3%)]. Classes showed distinct associations with clinically relevant external variables [e.g. somatization: odds ratio (OR) 8.1-12.3, and chronic stress: OR 3.7-4.4]. The Subclinical class reported symptomatology at subthreshold levels while experiencing disability. No pure depression or anxiety, but only mixed classes were found. CONCLUSIONS: An empirical classification model, incorporating both symptoms and disability identified clearly distinct cross-diagnostic subtypes, indicating that diagnostic nets should be cast wider than current phenomenology-based categorical systems.

Potentially curable recurrent disease after surgically managed non-metastatic renal cell carcinoma in low-, intermediate- and high-risk patients.

PURPOSE: Guidelines recommend risk-adapted follow-up (FU) strategies after (partial) nephrectomy in non-metastatic renal cell carcinoma (RCC). Since current systemic therapy does not cure metastatic RCC, only timely detected recurrence accessible for local therapy is potentially curable. This study analyzed the rate and management of potentially curable recurrences per risk group. METHODS: This is a retrospective study including non-metastatic RCC patients who underwent (partial) nephrectomy from 2004 to 2011, with a minimum follow-up of 4 years. Risk stratification was by Leibovich score (clear cell subtype) and UICC/AJCC grading (other subtypes). Recurrence, time to recurrence, symptoms and detection method were documented. Isolated local recurrence, solitary- and oligometastases (≤3 lesions, single site) were considered potentially curable. RESULTS: Among 234 patients, followed during a median of 61.9 months, 68 patients (29.1 %) developed a recurrence of which 28 (41.2 %) were considered potentially curable. The 5-year risk of recurrence for low-, intermediate- and high-risk patients was 7.8, 26.3 and 59.1 % of which 71.4, 52.2 and 23.1 % were considered potentially curable, respectively. In high-risk patients, incurable recurrence was detected after a median of 7.9 (3.7-17.2) months versus 13.9 (6-41.3) months for potentially curable lesions. Only 13 of potentially curable lesions (46 %) received local therapy. CONCLUSION: FU protocols should be adapted to the recurrence pattern of potentially curable disease. Most of the benefit may be achieved in intermediate-risk and high-risk-patients free of recurrence 1 year after surgery. Despite frequent imaging, only 13 patients (5.6 % of all patients followed) were managed with local therapy of whom only 4 remained free of disease.

Somatic mosaicism for the COL7A1 mutation p.Gly2034Arg in the unaffected mother of a patient with dystrophic epidermolysis bullosa pruriginosa.

Dystrophic epidermolysis bullosa (DEB) is a heritable blistering disorder caused by mutations in the type VII collagen gene, COL7A1. Although revertant mosaicism is well known in DEB, 'forward' somatic mosaicism, in which a pathogenic mutation arises on a wild-type (WT) background, extending beyond the germ cells, has not been reported. It is therefore unknown what proportion of sporadic dominant DEB (DDEB) cases result from de novo mutations or somatic mosaic parents. In the clinically unaffected mother of a patient with DDEB pruriginosa due to the p.Gly2034Arg mutation, we identified the p.Gly2034Arg mutation in a proportion of lymphocytes and skin cells (mutational load 10-25%). Our data emphasize that forward mosaicism occurs in DDEB and highlight that mutation analysis should always be performed in the parents of sporadic DDEB patients to confirm the de novo status of the mutation. Ultimately, this will reveal the frequency of true de novo mutations and somatic mosaicism in parents, which has important implications for genetic counselling. Our data indicate that the threshold of mutant type VII procollagen to develop DDEB must be higher than 10-25%, which provides a rationale for therapeutic approaches aimed at increasing the WT : mutant type VII collagen ratio.

RYR1-related myopathies: a wide spectrum of phenotypes throughout life.

BACKGROUND AND PURPOSE: Although several recent studies have implicated RYR1 mutations as a common cause of various myopathies and the malignant hyperthermia susceptibility (MHS) trait, many of these studies have been limited to certain age groups, confined geographical regions or specific conditions. The aim of the present study was to investigate the full spectrum of RYR1-related disorders throughout life and to use this knowledge to increase vigilance concerning malignant hyperthermia. METHODS: A retrospective cohort study was performed on the clinical, genetic and histopathological features of all paediatric and adult patients in whom an RYR1 mutation was detected in a national referral centre for both malignant hyperthermia and inherited myopathies (2008-2012). RESULTS: The cohort of 77 non-related patients (detection rate 28%) included both congenital myopathies with permanent weakness and 'induced' myopathies such as MHS and non-anaesthesia-related episodes of rhabdomyolysis or hyperCKemia, manifested throughout life and triggered by various stimuli. Sixty-one different mutations were detected, of which 24 were novel. Some mutations are present in both dominant (MHS) and recessive modes (congenital myopathy) of inheritance, even within families. Histopathological features included an equally wide spectrum, ranging from only subtle abnormalities to prominent cores. CONCLUSIONS: This broad range of RYR1-related disorders often presents to the general paediatric and adult neurologist. Its recognition is essential for genetic counselling and improving patients' safety during anaesthesia. Future research should focus on in vitro testing by the in vitro contracture test and functional characterization of the large number of RYR1 variants whose precise effects currently remain uncertain.

Evaluation of the diagnostic work-up in children with myocarditis and idiopathic dilated cardiomyopathy.

The underlying etiology of dilated cardiomyopathy (DCM) in children varies, 14-22% is secondary to myocarditis, and the majority remains idiopathic. Etiology has prognostic value; however, 'a clinical diagnosis of myocarditis' has been frequently used because the gold standard [endomyocardial biopsy (EMB)] is often not performed. Therefore, a consistent diagnostic approach and interpretation is needed. In this multicenter study, we evaluated the diagnostic approach and interpretation of the viral results in children with myocarditis and idiopathic DCM. We included 150 children with DCM, of whom 103 were assigned the diagnosis myocarditis (n = 21) or idiopathic DCM (n = 82) by the attending physician. Viral tests were performed in 97/103 patients, in only 34% (n = 35) some of the tests were positive. Of those patients, we evaluated the probability of the assigned diagnosis using the viral test results. We classified viral test results as reflecting definite or probable myocarditis in 14 children and possible or unlikely myocarditis in 21 children. Based on this classification, 23% of patients were misclassified. We found that in children with DCM, the diagnostic approach varied and the interpretation was mainly based on viral results. Since a 'clinical diagnosis of myocarditis' has been frequently used in daily practice because of the lack of EMB results, a uniform protocol is needed. We propose to use viral test results in several steps (blood PCR, serology, PCR and/or cultures of the gastro-intestinal and respiratory tract, and EMB results) to estimate the probability of myocarditis.