Clinical genetic diagnostics in Danish autosomal dominant polycystic kidney disease patients reveal possible founder variants

Background: Autosomal dominant polycystic kidney disease (ADPKD) is the most common heritable kidney disease. ADPKD leads to cysts, kidney enlargement and end-stage renal disease. ADPKD is mainly caused by variants in PKD1 and PKD2, with truncating PKD1 variants causing the most severe phenotype. This study aimed to characterize variants in Danish patients referred for screening of genes related to cystic kidney disease. Methods: 147 families were analysed for variants in PKD1, PKD2 and GANAB using next generation sequencing and multiplex ligation-dependent probe amplification. If a variant was identified, relatives were analysed for the specific variant using Sanger sequencing. Results: A pathogenic or possibly pathogenic variant was identified in 87% (103/118) of patients suspected to suffer from ADPKD, according to the requisition form. In total, 112 pathogenic or possibly pathogenic variants were observed, of which 94 were unique; 74 (79%) in PKD1 and 20 (21%) in PKD2, while 41 variants were novel. No variants in GANAB were observed. Ten recurrent variants were observed in 26 (26%) families. These were either PKD2 variants (N = 6) or non-truncating PKD1 variants (N = 4). Five of these were likely founder variants. Conclusions: The distribution of pathogenic or possibly pathogenic variants in the Danish ADPKD population is similar to that in other populations, except that recurrent truncating PKD1 variants appear to be rare, i.e. founder variants tend to be variant types associated with a mild phenotype. Patients with a mild phenotype may remain undiagnosed, consequently the frequency of founder variants and prevalence of ADPKD may be underestimated.</p

How doctors build community and socialize into a clinical department through morning reports. A positioning theory study

PHENOMENON: The morning report is one of the longest surviving hospital practices. Most studies of the morning report focus on the effectiveness of formal medical training, while focus on social and communicative aspects is rarer. This study explores the social interactions and communication in morning reports, examining the ways in which they contribute to the construction of professional identity and socialization into the community of the clinical department.APPROACH: We used a qualitative explorative design with video observations of morning reports. Our data consisted of 43 video-recorded observations (in all, 15.5 hours) from four different hospital departments in Denmark. These were analyzed using the theoretical framework of positioning theory.FINDINGS: A key finding was that each department followed its own individual structure. This order was not articulated as such but played out implictly. Two alternative storylines unfolded in the elements of the morning report: 1) being equal members of the specialty and department, and 2) preserving the hierarchical community and its inherent positions.INSIGHTS: The morning report can be seen as playing an important role in community making. It unfolds as a "dance" of repeated elements in a complex collegial space. Within this complexity, the morning report is a space for positioning oneself and others as a collegial "we", i.e., equal members of a department and specialty, at the same time as "having a place" in a hierarchal community. Thus, morning reports contribute to developing professional identity and socialization into the medical community.</p

Letter to the Editor-Recent advances in Lynch syndrome

Non peer reviewe

Functional megalin is expressed in renal cysts in a mouse model of adult polycystic kidney disease

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the progressive growth of cysts and a decline of renal function. The clinical feasibility of the number of potential disease-modifying drugs is limited by systemic adverse effects. We hypothesize that megalin, a multiligand endocytic receptor expressed in the proximal tubule, may be used to facilitate drug uptake into cysts, thereby allowing for greater efficacy and fewer side effects. METHODS: The cyst expression of various tubular markers, including megalin and aquaporin 2 (AQP2), was analysed by immunohistochemistry (IHC) of kidney sections from the ADPKD mouse model (PKD1(RC/RC)) at different post-natal ages. The endocytic function of megalin in cysts was examined by IHC of kidney tissue from mice injected with the megalin ligand aprotinin. RESULTS: Cyst lining epithelial cells expressing megalin were observed at all ages; however, the proportion decreased with age. Concomitantly, an increasing proportion of cysts revealed expression of AQP2, partial expression of megalin and/or AQP2 or no expression of the examined markers. Endocytic uptake of aprotinin was evident in megalin-positive cysts, but only in those that remained connected to the renal tubular system. CONCLUSIONS: Megalin-expressing cysts were observed at all ages, but the proportion decreased with age, possibly due to a switch in tubular origin, a merging of cysts of different tubular origin and/or a change in the expression pattern of cyst lining cells. Megalin expressed in cysts was functional, suggesting that megalin-mediated endocytosis is a potential mechanism for drug targeting in ADPKD if initiated early in the disease

Cancer risk and survival in path _ MMR carriers by gene and gender up to 75 years of age: a report from the prospective Lynch Syndrome database

Background Most patients with path_MMR gene variants (Lynch syndrome (LS)) now survive both their first and subsequent cancers, resulting in a growing number of older patients with LS for whom limited information exists with respect to cancer risk and survival. Objective and design This observational, international, multicentre study aimed to determine prospectively observed incidences of cancers and survival in path_MMR carriers up to 75 years of age. Results 3119 patients were followed for a total of 24 475 years. Cumulative incidences at 75 years (risks) for colorectal cancer were 46%, 43% and 15% in path_MLH1, path_MSH2 and path_MSH6 carriers; for endometrial cancer 43%, 57% and 46%; for ovarian cancer 10%, 17% and 13%; for upper gastrointestinal (gastric, duodenal, bile duct or pancreatic) cancers 21%, 10% and 7%; for urinary tract cancers 8%, 25% and 11%; for prostate cancer 17%, 32% and 18%; and for brain tumours 1%, 5% and 1%, respectively. Ovarian cancer occurred mainly premenopausally. By contrast, upper gastrointestinal, urinary tract and prostate cancers occurred predominantly at older ages. Overall 5-year survival for prostate cancer was 100%, urinary bladder 93%, ureter 85%, duodenum 67%, stomach 61%, bile duct 29%, brain 22% and pancreas 0%. Path_PMS2 carriers had lower risk for cancer. Conclusion Carriers of different path_MMR variants exhibit distinct patterns of cancer risk and survival as they age. Risk estimates for counselling and planning of surveillance and treatment should be tailored to each patient's age, gender and path_MMR variant. We have updated our open-access website www.lscarisk.org to facilitate this