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BA Vervaet et al.: CINAC, a toxin-induced lysosomal tubulopathy c l i n i c a l i n v e s t i g a t i o n Kidney International (2020) 97, 350-369 BA Vervaet et al.: CINAC, a toxin-induced lysosomal tubulopathy c l i n i c a l i n v e s t i g a t i o n

The beginning of the 21st century has seen the emergence of a new chronic tubulo-interstitial kidney disease of uncertain cause among agricultural communities in Central America and Sri Lanka. Despite many similarities in demography, presentation, clinical features, and renal histopathology in affected individuals in these regions, a toxic etiology has been considered mainly in Sri Lanka, whereas the predominant hypothesis in Central America has been that recurrent acute kidney injury (AKI) caused by heat stress leads to chronic kidney disease (CKD). This is termed the heat stress/dehydration hypothesis. This review attempts to demonstrate that there is sparse evidence for the occurrence of significant AKI among manual workers who are at high risk, and that there is little substantial evidence that an elevation of serum creatinine < 0.3 mg/dl in previously healthy people will lead to CKD even with recurrent episodes. It is also proposed that the extent of global warming over the last half-century was not sufficient to have caused a drastic change in the effects of heat stress on renal function in manual workers. Comparable chronic tubulo-interstitial kidney disease is not seen in workers exposed to heat in most tropical regions, although the disease is seen in individuals not exposed to heat stress in the affected regions. The proposed pathogenic mechanisms of heat stress causing CKD have not yet been proved in humans or demonstrated in workers at risk. It is believed that claims of a global warming nephropathy in relation to this disease may be premature and without convincing evidence.

Emergence of a new form of chronic kidney disease (CKD) of unknown etiology (CKDu) during the last 2 decades has resulted in considerable morbidity and mortality among the agricultural community residing in the north central region of Sri Lanka. A 3-level epidemiological case definition to identify CKDu in Sri Lanka was developed and published by the Ministry of Health in November 2016. The Sri Lanka Society of Nephrology (SLSON) refined the definition through a consensus of experts using a systematic approach in August 2017. An initial consultative meeting with the participation of 31 experts, including nephrology specialists, experts on primary care and epidemiology, and policy and university academics with long-standing experience in CKDu research, was held to identify the gaps in the existing definition. Following the meeting, a facilitator conducted 2 rounds of remote consultations using the Delphi method to obtain consensus of the participants on suggestions to improve the existing case definition. The process was initiated in August 2017 and was completed in April 2018 and resulted in the participants agreeing to a refined multilevel clinical case definition for CKDu to be used in surveillance and epidemiological studies. This article describes the process used and development of this new case definition for CKDu in Sri Lanka.

Chronic Kidney Disease (CKD) is a globally prevalent non-communicable disease with significant mortality and morbidity. It is typically associated with diabetes and hypertension; however, over the last two decades, an emergence of CKD of unknown etiology (CKDu) has claimed thousands of lives in several tropical agricultural communities. CKDu is associated with gradual loss of renal function without initial symptoms until reaching complete kidney failure and eventually death. The most impacted are young adult males of lower socio-economic strata. Since the disease progression can be successfully attenuated through early detection, the development of superior screening and management measures is of utmost importance. In contrast to the conventional biomarkers, novel biomarkers with improved sensitivity and specificity are being discussed as promising tools for early diagnosis of the disease. This review summarizes emerging novel biomarkers used in assessing CKD and discusses the current utility and diagnostic potential of such biomarkers for CKDu screening in clinical settings of different communities impacted by CKDu. Our goal is to provide a framework for practitioners in CKDu impacted regions to consider the use of these novel biomarkers through this synthesis. The increased use of these biomarkers will not only help to validate their diagnostic power further and establish potential prognostic value but may also provide critical insights into sites and mechanisms of renal damage.

South and Southeast Asia is the most populated, heterogeneous part of the world. The Association of Vascular Access and InTerventionAl Renal physicians (AVATAR Foundation), India, gathered trends on epidemiology and Interventional Nephrology (IN) for this region. The countries were divided as upper-middle- and higher-income countries as Group-1 and lower and lower-middle-income countries as Group-2. Forty-three percent and 70% patients in the Group 1 and 2 countries had unplanned hemodialysis (HD) initiation. Among the incident HD patients, the dominant Vascular Access (VA) was non-tunneled central catheter (non-TCC) in 70% of Group 2 and tunneled central catheter (TCC) in 32.5% in Group 1 countries. Arterio-Venous Fistula (AVF) in the incident HD patients was observed in 24.5% and 35% of patients in Group-2 and Group-1, respectively. Eight percent and 68.7% of the prevalent HD patients in Group-2 and Group-1 received HD through an AVF respectively. Nephrologists performing any IN procedure were 90% and 60% in Group-2 and Group 1, respectively. The common procedures performed by nephrologists include renal biopsy (93.3%), peritoneal dialysis (PD) catheter insertion (80%), TCC (66.7%) and non-TCC (100%). Constraints for IN include lack of time (73.3%), lack of back-up (40%), lack of training (73.3%), economic issues (33.3%), medico-legal problems (46.6%), no incentive (20%), other interests (46.6%) and institution not supportive (26%). Routine VA surveillance is performed in 12.5% and 83.3% of Group-2 and Group-1, respectively. To conclude, non-TCC and TCC are the most common vascular access in incident HD patients in Group-2 and Group-1, respectively. Lack of training, back-up support and economic constraints were main constraints for IN growth in Group-2 countries.

BackgroundGitelman syndrome (GS) is a rare autosomal recessively inherited salt-wasting tubulopathy associated with mutations in the SLC12A3 gene, which encodes for NaCl cotransporter (NCC) in the kidney.Case presentationIn this report, we describe two siblings from a Sri Lankan non-consanguineous family presenting with hypokalaemia associated with renal potassium wasting, hypomagnesemia, hypocalciuria and hypereninemic hyperaldosteronism with normal blood pressure. Genetic testing showed that both were homozygotes for a novel missense mutation in exon 10 of the SLC12A3 gene [NM_000339.2, c.1276A > T; p.N426Y], which has not previously been reported in the literature in association with GS. Their mother was a heterozygous carrier for the same mutation. The father was not alive at the time of testing. This novel mutation extends the spectrum of known SLC12A3 gene mutations and further supports the allelic heterogeneity of GS. Interestingly both siblings had young onset Diabetes with strong family history.ConclusionThese findings have implications in providing appropriate genetic counseling to the family with regard to the risk associated with inbreeding, the detection of carrier/presymptomatic relatives. It further expands the known spectrum of genotypic and phenotypic characteristics of Gitelman syndrome.

Aim There is paucity of data on the epidemiology of end‐stage kidney disease (ESKD) from South Asia and South‐East Asia. The objective of this study was to assess the aetiology, practice patterns and disease burden and growth of ESKD in the region comparing the economies. Methods The national nephrology societies of the region; responded to the questionnaire; based on latest registries, acceptable community‐based studies and society perceptions. The countries in the region were classified into Group 1 (High|higher‐middle‐income) and Group 2 (lower|lowermiddle income). Student t‐test, Mann‐Whitney U test and Fisher's exact test were used for comparison. Results Fifteen countries provided the data. The average incidence of ESKD was estimated at 226.7 per million population (pmp), (Group 1 vs. Group 2, 305.8 vs. 167.8 pmp) and average prevalence at 940.8 pmp (Group 1 vs. Group 2, 1306 vs. 321 pmp). Group 1 countries had a higher incidence and prevalence of ESKD. Diabetes, hypertension and chronic glomerulonephritis were most common causes. The mean age in Group 2 was lower by a decade (Group 1 vs. Group 2—59.45 vs 47.7 years). Conclusion Haemodialysis was the most common kidney replacement therapy in both groups and conservative management of ESKD was the second commonest available treatment option within Group 2. The disease burden was expected to grow >20% in 50% of Group 1 countries and 78% of Group 2 countries along with the parallel growth in haemodialysis and peritoneal dialysis.