Novel and Founder Pathogenic Variants in X-Linked Alport Syndrome Families in Greece.

Alport syndrome (AS) is the most frequent monogenic inherited glomerulopathy and is also genetically and clinically heterogeneous. It is caused by semi-dominant pathogenic variants in the X-linked COL4A5 (NM_000495.5) gene or recessive variants in the COL4A3/COL4A4 (NM_000091.4/NM_000092.4) genes. The disease manifests in early childhood with persistent microhematuria and can progress to proteinuria and kidney failure in adolescence or early adulthood if left untreated. On biopsy, pathognomonic features include alternate thinning, thickening and lamellation of the glomerular basement membrane (GBM), in the presence of podocyte foot process effacement. Although previous studies indicate a prevalence of AS of about 1/50,000, a recent publication reported a predicted rate of pathogenic COL4A5 variants of 1/2320. We herewith present 98 patients (40 M/58 F) from 26 Greek families. We are selectively presenting the families segregating the X-linked form of AS with pathogenic variants in the COL4A5 gene. We found 21 different pathogenic variants, 12 novel: eight glycine and one proline substitutions in the collagenous domain, one cysteine substitution in the NC1 domain, two premature termination of translation codons, three splicing variants, one 5-bp insertion/frameshift variant, one indel-frameshift variant and four gross deletions. Notably, patients in six families we describe here and three families we reported previously, carried the COL4A5-p.G624D substitution, a founder defect encountered all over Europe which is hypomorphic with mostly milder symptomatology. Importantly, on several occasions, the correct genetic diagnosis reclassified patients as patients with AS, leading to termination of previous immunosuppressive/cyclosporine A therapy and a switch to angiotensin converting enzyme inhibitors (ACEi). With the understanding that all 98 patients span a wide range of ages from infancy to late adulthood, 15 patients (11 M/4 F) reached kidney failure and 11 (10 M/1 F) received a transplant. The prospects of avoiding lengthy diagnostic investigations and erroneous medications, and the advantage of delaying kidney failure with very early administration of renin-angiotensin-aldosterone system (RAAS) blockade, highlights the importance of timely documentation of AS by genetic diagnosis.

Low T3 syndrome and long-term mortality in chronic hemodialysis patients.

AIM: To investigate the predictive value of low freeT3 for long-term mortality in chronic hemodialysis (HD) patients and explore a possible causative role of chronic inflammation. METHODS: One hundred fourteen HD patients (84 males) consecutively entered the study and were assessed for thyroid function and two established markers of inflammation, high sensitivity C-reactive protein (hsCRP) and interleukin-6 (IL-6). Monthly blood samples were obtained from all patients for three consecutive months during the observation period for evaluation of thyroid function and measurement of inflammatory markers. The patients were then divided in two groups based on the cut-off value of 1.8 pg/mL for mean plasma freeT3, and were prospectively studied for a mean of 50.3 ± 30.8 mo regarding cumulative survival. The prognostic power of low serum fT3 levels for mortality was assessed using the Kaplan-Meier method and univariate and multivariate regression analysis. RESULTS: Kaplan-Meier survival curve showed a negative predictive power for low freeT3. In Cox regression analysis low freeT3 remained a significant predictor of mortality after adjustment for age, diabetes mellitus, hypertension, hsCRP, serum creatinine and albumin. Regarding the possible association with inflammation, freeT3 was correlated with hsCRP, but not IL-6, and only at the first month of the study. CONCLUSION: In chronic hemodialysis patients, low plasma freeT3 is a significant predictor of all-cause mortality. Further studies are required to identify the underlying mechanisms of this association.

Multicenter epidemiological study to assess the population of CKD patients in Greece: results from the PRESTAR study.

BACKGROUND: Chronic Kidney Disease (CKD) is a relatively common condition not only associated with increased morbidity and mortality but also fuelling End Stage Renal Disease (ESRD). Among developed nations, Greece has one of the highest ESRD incidence rates, yet there is limited understanding of the epidemiology of earlier stages of CKD. METHODS: Cross-sectional survey of pre-dialysis CKD outpatients in nephrology clinics in the National Health Care system between October 2009 and October 2010. Demographics, cause of CKD, blood pressure, level of renal function, duration of CKD and nephrology care, and specialty of referral physician were collected and analyzed. Different methods for estimating renal function (Cockroft-Gault [CG], CKD-Epi and MDRD) and staging CKD were assessed for agreement. RESULTS: A total of 1,501 patients in 9 centers were enrolled. Diabetic nephropathy was the most common nephrologist assigned cause of CKD (29.7%). In total, 36.5% of patients had self-referred to the nephrologist; patients with diabetes or serum creatinine above 220 µmol/l (eGFR<40 ml/min/1.73 m2) were more likely to have been referred by a physician. Agreement between MDRD and CKD-Epi, but not between CG, the other estimating equations, was excellent. There was substantial heterogeneity with respect to renal diagnoses, referral patterns and blood pressure among participating centers. CONCLUSIONS: In this first epidemiologic assessment of CKD in Greece, we documented delayed referral and high rates of self-referral among patients with CKD. eGFR reporting, currently offered by a limited number of laboratories, may facilitate detection of CKD at an earlier, more treatable stage.

Unit dosing of darbepoetin alfa for thetreatment of anemia in patients with end-stage renal disease being switched from recombinant human erythropoietin: Results of a phase IIIb, 27-week, multicenter, open-label study in Greek patients.

BACKGROUND: Darbepoetin alfa is an erythropoietis-stimulating glycoprotein with a ∼3-fold longer t1/2 and greater biological activity compared with recombinant human erythropoietin (rHuEPO). OBJECTIVE: The objective of this study was to evaluate the efficacy andtolerability of long-term (24-week) darbepoetin alfa treatment in maintaining hemoglobin (Hb) concentrations in the target range of 10 to 13 g/dL in patients undergoing dialysis; the patients were switched from rHuEPO to a less-frequent dosing regimen of darbepoetin alfa without an increase in dose. METHODS: In this Phase IIlb, open-label, multicenter study, patients withend-stage renal disease (ESRD) undergoing dialysis who were receiving rHuEPO BIW or TIW at baseline were switched to darbepoetin alfa QW; patients receiving rHuEPO QW were switched to darbepoetin alfa Q2W Administration of darbepoetin alfa was by the same route as previous rHuEPO administration (IV or SC). Patients received darbepoetin alfa for 24 weeks, including a 20-week drug titration period followed by a 4-week, stable-dose evaluation period. The mode, dose, and frequency of administration of darbepoetin alfa were compared with those of baseline rHuEPO. Tolerability assessment was based on spontaneous reporting and laboratory tests (hematology, vital sign measurement, iron status, and biochemistry). RESULTS: The study comprised 173 patients who were divided into 2 groups by route of administration (IV group, n = 146; SC group, n = 27). Mean (SE) adjusted increases in Hb concentration from baseline to the evaluation period for patients receiving darbepoetin alfa QW were 0.94 (0.32) g/dL and 0.38 (0.30) g/dL for the IV or SC routes, respectively (P = 0.004 and NS, respectively). For patients receiving darbepoetin alfa Q2W the mean (SE) adjusted increases in Hb concentration were 0.08 (0.53) g/dL and 0.48 (0.35) g/dL for the IV and SC routes, respectively (both, P = NS). No significant differences in IV/SC dose ratio were observed between the 2 routes of administration. In addition, no increases in darbepoetin alfa dose were observed. The most commonly reported adverse events were hypertension (8 patients [5%]) and vascular access thrombosis (4 [2%]). The incidence of treatment-related adverse events was 6 (3%). CONCLUSIONS: Darbepoetin alfa effectively maintained Hb concentrations within the target range without an increase in dose, even at a reduced dosing frequency. Overall, darbepoetin alfa was well tolerated.