A novel COL4A1 frameshift mutation in familial kidney disease: the importance of the C-terminal NC1 domain of type IV collagen.

BACKGROUND: Hereditary microscopic haematuria often segregates with mutations of COL4A3, COL4A4 or COL4A5 but in half of families a gene is not identified. We investigated a Cypriot family with autosomal dominant microscopic haematuria with renal failure and kidney cysts. METHODS: We used genome-wide linkage analysis, whole exome sequencing and cosegregation analyses. RESULTS: We identified a novel frameshift mutation, c.4611_4612insG:p.T1537fs, in exon 49 of COL4A1. This mutation predicts truncation of the protein with disruption of the C-terminal part of the NC1 domain. We confirmed its presence in 20 family members, 17 with confirmed haematuria, 5 of whom also had stage 4 or 5 chronic kidney disease. Eleven family members exhibited kidney cysts (55% of those with the mutation), but muscle cramps or cerebral aneurysms were not observed and serum creatine kinase was normal in all individuals tested. CONCLUSIONS: Missense mutations of COL4A1 that encode the CB3 [IV] segment of the triple helical domain (exons 24 and 25) are associated with HANAC syndrome (hereditary angiopathy, nephropathy, aneurysms and cramps). Missense mutations of COL4A1 that disrupt the NC1 domain are associated with antenatal cerebral haemorrhage and porencephaly, but not kidney disease. Our findings extend the spectrum of COL4A1 mutations linked with renal disease and demonstrate that the highly conserved C-terminal part of the NC1 domain of the α1 chain of type IV collagen is important in the integrity of glomerular basement membrane in humans

HNF1B Genetic Testing In a Turkish Cypriot Population with a High Incidence of Familial Kidney Disease

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Incidence of end-stage renal disease in the Turkish-Cypriot population of Northern Cyprus: a population based study.

BACKGROUND: This is the first report of the incidence and causes of end-stage renal disease (ESRD) of the Turkish-Cypriot population in Northern Cyprus. METHODS: Data were collected over eight consecutive years (2004-2011) from all those starting renal replacement therapy (RRT) in this population. Crude and age-standardised incidence at 90 days was calculated and comparisons made with other national registries. We collected DNA from the entire prevalent population. As an initial experiment we looked for two genetic causes of ESRD that have been reported in Greek Cypriots. RESULTS: Crude and age-standardised incidence at 90 days was 234 and 327 per million population (pmp) per year, respectively. The mean age was 63, and 62% were male. The age-adjusted prevalence of RRT in Turkish-Cypriots was 1543 pmp on 01/01/2011. The incidence of RRT is higher than other countries reporting to the European Renal Association - European Dialysis and Transplant Association, with the exception of Turkey. Diabetes is a major cause of ESRD in those under 65, accounting for 36% of incident cases followed by 30% with uncertain aetiology. 18% of the incident population had a family history of ESRD. We identified two families with thin basement membrane nephropathy caused by a mutation in COL4A3, but no new cases of CFHR5 nephropathy. CONCLUSIONS: This study provides the first estimate of RRT incidence in the Turkish-Cypriot population, describes the contribution of different underlying diagnoses to ESRD, and provides a basis for healthcare policy planning

Can we improve the diagnosis of renal failure? A revised coding system for the Middle East and North Africa

We reviewed the regional data on primary renal disease (PRD) causing end-stage renal failure (ESRF) during the decade 2000-2009. Reporting was generally inconsistent and diagnostic groups were poorly defined. We propose a system in which all diagnoses fall into one of eight broad groups: ESRF of uncertain etiology, congenital abnormalities of the kidney and urinary tract (CAKUT) and acquired uropathy, glomerular diseases, tubulo-interstitial disease (TID), other congenital and familial diseases, diabetes, renovascular disease and other specified diagnoses. Each group has sub-headings; for instance, primary glomerulonephritis, secondary glomerulonephritis, and hereditary glomerular disease. For each sub-heading, there is a list of specific diagnoses similar to that used by the European Dialysis and Transplant Association (EDTA) and United States Renal Data System (USRDS) coding systems. We also recommend that "etiology unknown" group should be reported in more detail as either "glomerular phenotype" or "tubular phenotype" and careful attention be paid to evidence for a family history of renal disease. To improve reporting, all patients who are diabetic, and all who have evidence of familial inheritance, should be recorded and a diagnostic category should be chosen. Thus, a diabetic patient is designated as "diabetic nephropathy" only if he/she fulfils the case definition for that diagnosis. We believe that the collection can be done much better as exemplified by the pediatric community, where data collection is very consistent, and there is a low rate of "unknown disease"

Obligatory referral among other factors associated with peritonitis in peritoneal dialysis patients

Aim: Peritonitis is one of the major comorbidities of peritoneal dialysis (PD) patients. The aim of this study was to concentrate on potential risk factors, including more recently studied ones among the classical ones for peritonitis, in PD patients. Materials and methods: We analysed 109 patients (F/M = 42/67) followed up at least for 3 months in a single centre, a tertiary referral hospital for 360.1 patient years. In the study which is designed as a retrospective cohort study, demographic characteristics, conditions for choosing PD, type of PD treatment, some chemical tests and peritonitis episodes were recorded from the files of the patients. Results: The rate of peritonitis was found to be 0.22 episode/patient year and 22 (20.18%) of the patients had more than one episode. Twenty seven (24.8%) of the patients were allocated to PD due to obligatory reasons. According to multiple regression analysis, the assosciated factors were found to be PD allocation type (obligatory versus voluntary) (p = 0.04; RR = 2.6), serum albumin level (p = 0.05; RR = 1.2), and anti-hepatitis C Virus Antibody positivity (p = 0.03; RR = 1.6). Frequency of female patients were significantly higher in the group who had multiple episodes (p = 0.01). Conclusion: Obligatory referral which can be an indication of loss of motivation for peritoneal dialysis procedures, is thought to be a strong risk factor for peritonitis in PD patients and should be further studied. Patients with multiple episodes had a higher frequency of obligatory referral as expected and additionally, they were higher in number of females when compared to the ones with single episode

A rare cause of focal segmental glomerulosclerosis: Sarcoidosis

A 58-year-old female patient diagnosed as having sarcoidosis 23 years ago developed nephrotic syndrome. No pathology was found which could explain this, so it was attributed to her sarcoidosis. Renal biopsy showed global and segmental sclerosis. The occurrence of focal segmentary glomerulosclerosis in a case of sarcoidosis is rare. In systemic sarcoidosis it is thought that T-cell dysfunction may play a role in the pathogenesis of glomerulonephritis. When treatment is considered, corticosteroid therapy may be used according to the clinical status at diagnosis as well as on follow-up of the patient. Copyright (C) 2002 S. KargerAG, Basel

The importance of complement levels and clinical characteristics of primary membranoproliferative glomerulonephritis in Turkey

Abstract Not Availabl

Lateral mass screw stimulation thresholds in posterior cervical instrumentation surgery: a predictor of medial deviation.

OBJECTIVE Normative data exists for stimulus-evoked pedicle screw electromyography (EMG) current thresholds in the lumbar spine, and is routinely referenced during spine surgeries to detect a screw breach, prevent injury of neural elements, and ensure the most biomechanically sound instrumentation construct. To date, similar normative data for cervical lateral mass screws is limited, thus the utility of lateral mass screw testing remains unclear. To address this disparity, in this study the authors describe cumulative lateral mass screw stimulation threshold data in patients undergoing posterior cervical instrumentation with lateral mass screws. These data are correlated with screw placement on postoperative imaging, and a novel correlation is discovered with direct clinical implications. METHODS Using a ball-tip probe, 154 lateral mass screws in 21 patients were electrically tested intraoperatively. In each case, for each screw, the lowest (or threshold) current at which the first polyphasic stimulus-evoked EMG response was reproducibly observed by a neurophysiologist was recorded. All patients underwent postoperative CT. Screw position within the lateral mass was first measured in the axial and sagittal planes for each lateral mass screw using the CT images. Screw placement was also evaluated by 2 independent physicians, blinded to current threshold data, on a binary scale of acceptability. The predictive capacity of screw EMG threshold data was evaluated via multivariable regression analyses and receiver operating characteristic (ROC) analyses. Predictive capacity was examined with respect to screw position within the lateral mass, as well as screw acceptability. RESULTS Lateral mass screw EMG thresholds did not appear to differ significantly for screws considered "acceptable" versus "unacceptable" according to the radiographic criteria. Accordingly, ROC analysis confirmed that EMG current threshold data were of minimal utility in predicting screw radiographic acceptability. However, EMG threshold was significantly predictive of screw medial distance from the spinal canal. A screw stimulating below 7.5 mA correctly identified a screw as being within 2 mm of the spinal canal with 75% sensitivity and 92% specificity (positive predictive value 20%, negative predictive value 99.3%), independent of its distance relative to other lateral mass landmarks. EMG current threshold was not significantly predictive of screw deviation in the superior or inferior directions, and was inversely predictive of screw deviations in the lateral direction. CONCLUSIONS In the context of uncertainty regarding the utility of cervical lateral mass EMG current threshold data, this study found that EMG current thresholds correspond significantly, and exclusively, with screw distance from the spinal canal. This association appears independent of other criteria for screw misplacement. As such, the authors recommend that EMG current thresholds be referenced in the case of a suspected medial breach as an effective means to rule out screw placement too medial to the spinal canal