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Despite a large number of people globally being affected by rare kidney diseases, research support and health care policy programs usually focus on the management of the broad spectrum of CKD without particular attention to rare causes that would require a targeted approach for proper cure. Hence, specific curative approaches for rare kidney diseases are scarce, and these diseases are not treated optimally, with implications on the patients' health and quality of life, on the cost for the health care system, and society. There is therefore a need for rare kidney diseases and their mechanisms to receive the appropriate scientific, political, and policy attention to develop specific corrective approaches. A wide range of policies are required to address the various challenges that target care for rare kidney diseases, including the need to increase awareness, improve and accelerate diagnosis, support and implement therapeutic advances, and inform the management of the diseases. In this article, we provide specific policy recommendations to address the challenges hindering the provision of targeted care for rare kidney diseases, focusing on awareness and prioritization, diagnosis, management, and therapeutic innovation. In combination, the recommendations provide a holistic approach aiming for all aspects of rare kidney disease care to improve health outcomes, reduce the economic effect, and deliver benefits to society. Greater commitment from all the key stakeholders is now needed, and a central role should be assigned to patients with rare kidney disease to partner in the design and implementation of potential solutions., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of American Society of Nephrology.)

Background and Objectives: C3 glomerulopathy and idiopathic Ig-associated membranoproliferative GN are kidney diseases characterized by abnormal glomerular complement C3 deposition. These conditions are heterogeneous in outcome, but approximately 50% of patients develop kidney failure within 10 years., Design, Setting, Participants, & Measurements: To improve identification of patients with poor prognosis, we performed a detailed analysis of percutaneous kidney biopsies in a large cohort of patients. Using a validated histologic scoring system, we analyzed 156 native diagnostic kidney biopsies from a retrospective cohort of 123 patients with C3 glomerulopathy and 33 patients with Ig-associated membranoproliferative GN. We used linear regression, survival analysis, and Cox proportional hazards models to assess the relationship between histologic and clinical parameters with outcome., Results: Frequent biopsy features were mesangial expansion and hypercellularity, glomerular basement membrane double contours, and endocapillary hypercellularity. Multivariable analysis showed negative associations between eGFR and crescents, interstitial inflammation, and interstitial fibrosis/tubular atrophy. Proteinuria positively associated with endocapillary hypercellularity and glomerular basement membrane double contours. Analysis of second native biopsies did not demonstrate associations between immunosuppression treatment and improvement in histology. Using a composite outcome, risk of progression to kidney failure associated with eGFR and proteinuria at the time of biopsy, cellular/fibrocellular crescents, segmental sclerosis, and interstitial fibrosis/tubular atrophy scores., Conclusions: Our detailed assessment of kidney biopsy data indicated that cellular/fibrocellular crescents and interstitial fibrosis/tubular atrophy scores were significant determinants of deterioration in kidney function., (Copyright © 2022 by the American Society of Nephrology.)

Background and Objectives: In contrast to shigatoxin-associated Escherichia coli (STEC) causing hemolytic uremic syndrome, STEC-unrelated infections associated with thrombotic microangiopathy are less characterized., Design, Setting, Participants, & Measurements: Our retrospective study in a four-hospital institution of 530 consecutive patients with adjudicated thrombotic microangiopathies during the 2009-2016 period studied STEC-unrelated infections' epidemiology and major outcomes (death, acute dialysis, and major cardiovascular events)., Results: STEC-unrelated infection was present in 145 of 530 (27%) patients, thrombotic microangiopathies without infection were present in 350 of 530 (66%) patients, and STEC causing hemolytic and uremic syndrome was present in 35 of 530 (7%) patients. They (versus thrombotic microangiopathy without infection) were associated with age >60 years (36% versus 18%), men (53% versus 27%), altered consciousness (32% versus 11%), mean BP <65 mm Hg (21% versus 4%), lower hemoglobin and platelet count, and AKI (72% versus 49%). They were associated with more than one pathogen in 36 of 145 (25%) patients (either isolated [14%] or combined [86%] to other causes of thrombotic microangiopathy); however, no significant clinical or biologic differences were noted between the two groups. They were more frequently due to bacteria (enterobacteria [41%], Staphylococcus aureus [11%], and Streptococcus pneumonia [3%]) than viruses (Epstein-Barr [20%], cytomegalovirus [18%], influenza [3%], hepatitis C [1%], HIV [1%], and rotavirus [1%]). STEC-unrelated infections were independent risk factors for in-hospital death (odds ratio, 2.22; 95% confidence interval, 1.18 to 4.29), major cardiovascular event (odds ratio, 3.43; 95% confidence interval, 1.82 to 6.69), and acute dialysis (odds ratio, 3.48; 95% confidence interval, 1.78 to 7.03). Bacteria (versus other pathogens), and among bacteria, enterobacteria, presence of more than one bacteria, and E. coli without shigatoxin were risk factors for acute dialysis., Conclusions: Infections are frequent thrombotic microangiopathy triggers or causes, and they are mostly unrelated to STEC. Infections convey a higher risk of death and major complications. The most frequent pathogens were enterobacteria, S. aureus , Epstein-Barr virus, and cytomegalovirus., Podcast: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021&#95;09&#95;07&#95;CJN17511120.mp3., (Copyright © 2021 by the American Society of Nephrology.)

Background and Objectives: Thrombotic microangiopathies constitute a diagnostic and therapeutic challenge. Secondary thrombotic microangiopathies are less characterized than primary thrombotic microangiopathies (thrombotic thrombocytopenic purpura and atypical hemolytic and uremic syndrome). The relative frequencies and outcomes of secondary and primary thrombotic microangiopathies are unknown., Design, Setting, Participants, & Measurements: We conducted a retrospective study in a four-hospital institution in 564 consecutive patients with adjudicated thrombotic microangiopathies during the 2009-2016 period. We estimated the incidence of primary and secondary thrombotic microangiopathies, thrombotic microangiopathy causes, and major outcomes during hospitalization (death, dialysis, major cardiovascular events [acute coronary syndrome and/or acute heart failure], and neurologic complications [stroke, cognitive impairment, or epilepsy])., Results: We identified primary thrombotic microangiopathies in 33 of 564 patients (6%; thrombotic thrombocytopenic purpura: 18 of 564 [3%]; atypical hemolytic and uremic syndrome: 18 of 564 [3%]). Secondary thrombotic microangiopathies were found in 531 of 564 patients (94%). A cause was identified in 500 of 564 (94%): pregnancy (35%; 11 of 1000 pregnancies), malignancies (19%), infections (33%), drugs (26%), transplantations (17%), autoimmune diseases (9%), shiga toxin due to Escherichia coli (6%), and malignant hypertension (4%). In the 31 of 531 patients (6%) with other secondary thrombotic microangiopathies, 23% of patients had sickle cell disease, 10% had glucose-6-phosphate dehydrogenase deficiency, and 44% had folate deficiency. Multiple causes of thrombotic microangiopathies were more frequent in secondary than primary thrombotic microangiopathies (57% versus 19%; P <0.001), and they were mostly infections, drugs, transplantation, and malignancies. Significant differences in clinical and biologic differences were observed among thrombotic microangiopathy causes. During the hospitalization, 84 of 564 patients (15%) were treated with dialysis, 64 of 564 patients (11%) experienced major cardiovascular events, and 25 of 564 patients (4%) had neurologic complications; 58 of 564 patients (10%) died, but the rates of complications and death varied widely by the cause of thrombotic microangiopathies., Conclusions: Secondary thrombotic microangiopathies represent the majority of thrombotic microangiopathies. Multiple thrombotic microangiopathies causes are present in one half of secondary thrombotic microangiopathies. The risks of dialysis, neurologic and cardiac complications, and death vary by the cause of thrombotic microangiopathies., (Copyright © 2019 by the American Society of Nephrology.)

Background: Pregnancy is associated with various forms of thrombotic microangiopathy, including hemolytic uremic syndrome. A previous small French study suggested that pregnancy-associated hemolytic uremic syndrome was to be included in the spectrum of atypical hemolytic uremic syndrome linked to complement alternative pathway dysregulation., Design, Setting, Participants, & Measurements: We sought to retrospectively analyze the presentation, outcome, and frequency of complement alternative pathway gene variants in a larger international (France, United Kingdom, Italy) cohort of patients with pregnancy-associated hemolytic uremic syndrome., Results: Eighty-seven patients with pregnancy-associated hemolytic uremic syndrome were included. Hemolytic uremic syndrome occurred mainly during the first pregnancy (58%) and in the postpartum period (76%). At diagnosis, 56 (71%) patients required dialysis. Fifty-six (78%) patients underwent plasma exchanges, 21 (41%) received plasma infusions, and four (5%) received eculizumab. During follow-up (mean duration of 7.2 years), 41 (53%) patients reached ESRD, 15 (19%) had CKD, and 18 (28%) patients experienced hemolytic uremic syndrome relapse. Twenty-four patients (27%) received a kidney transplant and a recurrence of hemolytic uremic syndrome occurred in 13 (54%) patients. Variants in complement genes were detected in 49 (56%) patients, mainly in the CFH (30%) and CFI genes (9%)., Conclusions: Pregnancy-associated hemolytic uremic syndrome and atypical hemolytic uremic syndrome nonrelated to pregnancy have the same severity at onset and during follow-up and the same frequency of complement gene variants., (Copyright © 2017 by the American Society of Nephrology.)

Background and Objectives: The complement inhibitor eculizumab has dramatically improved the outcome of atypical hemolytic uremic syndrome. However, the optimal duration of eculizumab treatment in atypical hemolytic uremic syndrome remains debated. We report on the French atypical hemolytic uremic syndrome working group's first 2-year experience with eculizumab discontinuation in patients with atypical hemolytic uremic syndrome., Design, Setting, Participants & Measurements: Using the French atypical hemolytic uremic syndrome registry database, we retrospectively identified all dialysis-free patients with atypical hemolytic uremic syndrome who discontinued eculizumab between 2010 and 2014 and reviewed their relevant clinical and biologic data. The decision to discontinue eculizumab was made by the clinician in charge of the patient. All patients were closely monitored by regular urine dipsticks and blood tests. Eculizumab was rapidly (24-48 hours) restarted in case of relapse., Results: Among 108 patients treated with eculizumab, 38 patients (nine children and 29 adults) discontinued eculizumab (median treatment duration of 17.5 months). Twenty-one patients (55%) carried novel or rare complement genes variants. Renal recovery under eculizumab was equally good in patients with and those without complement gene variants detected. After a median follow-up of 22 months, 12 patients (31%) experienced atypical hemolytic uremic syndrome relapse. Eight of 11 patients (72%) with complement factor H variants, four of eight patients (50%) with membrane cofactor protein variants, and zero of 16 patients with no rare variant detected relapsed. In relapsing patients, early reintroduction (≤48 hours) of eculizumab led to rapid (<7 days) hematologic remission and a return of serum creatinine to baseline level in a median time of 26 days. At last follow-up, renal function remained unchanged in nonrelapsing and relapsing patients compared with baseline values before eculizumab discontinuation., Conclusions: Pathogenic variants in complement genes were associated with higher risk of atypical hemolytic uremic syndrome relapse after eculizumab discontinuation. Prospective studies are needed to identify biomarkers predictive of relapse and determine the best strategy of retreatment in relapsing patients., (Copyright © 2016 by the American Society of Nephrology.)

Background and Objectives: Atypical hemolytic uremic syndrome (aHUS) is a rare complement-mediated kidney disease that was first recognized in children but also affects adults. This study assessed the disease presentation and outcome in a nationwide cohort of patients with aHUS according to the age at onset and the underlying complement abnormalities., Design, Setting, Participants, & Measurements: A total of 214 patients with aHUS were enrolled between 2000 and 2008 and screened for mutations in the six susceptibility factors for aHUS and for anti-factor H antibodies., Results: Onset of aHUS occurred as frequently during adulthood (58.4%) as during childhood (41.6%). The percentages of patients who developed the disease were 23%, 40%, 70%, and 98% by age 2, 18, 40, and 60 years, respectively. Mortality was higher in children than in adults (6.7% versus 0.8% at 1 year) (P=0.02), but progression to ESRD after the first aHUS episode was more frequent in adults (46% versus 16%; P<0.001). Sixty-one percent of patients had mutations in their complement genes. The renal outcome was not significantly different in adults regardless of genetic background. Only membrane cofactor protein (MCP) and undetermined aHUS were less severe in children than adults. The frequency of relapse after 1 year was 92% in children with MCP-associated HUS and approximately 30% in all other subgroups., Conclusion: Mortality rate was higher in children than adults with aHUS, but renal prognosis was worse in adults than children. In children, the prognosis strongly depends on the genetic background.

AKI in pregnancy remains a cause of significant fetomaternal mortality and morbidity, particularly in developing countries. Hypertensive complications of pregnancy (preeclampsia/eclampsia or hemolysis, elevated liver enzymes, and low platelets count syndrome) are the leading cause of AKI in pregnancy worldwide. Thrombotic microangiopathy is another peculiar and devastating cause of AKI in pregnancy. During the last decade, our understanding, and in some cases, our management, of these causes of AKI in pregnancy has dramatically improved. For instance, convincing data have linked pre-eclampsia/eclampsia to an increase in circulating antiangiogenic factors soluble Flt 1 and endoglin, which induce endothelial cell dysfunction, hypertension, and proteinuria. Several distinct pathogenic mechanisms underlying thrombotic microangiopathy, including thrombotic microangiopathy occurring during pregnancy, have been established. Thrombotic microangiopathy, which can present as hemolytic uremic syndrome or thrombotic thrombocytopenic purpura, can be reclassified in four potentially overlapping subtypes: disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 deficiency-related thrombotic microangiopathy, complement alternative pathway dysregulation-related thrombotic microangiopathy, secondary thrombotic microangiopathy (verotoxin and antiangiogenic drugs), and thrombotic microangiopathy of undetermined mechanism. In most cases, pregnancy is only a precipitating factor for thrombotic microangiopathy. Treatment of thrombotic microangiopathy occurring during pregnancy should be tailored to the underlying pathogenic mechanism: (1) restoration of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 serum activity in the setting of thrombotic thrombocytopenic purpura through plasma exchanges and in some cases, B cell-depleting therapy and (2) inhibition of complement alternative pathway activation in atypical hemolytic uremic syndrome using antiC5 blocking antibody (eculizumab).

Background and Objectives: Several different entities have recently been described among glomerular diseases associated with monoclonal IgG deposits. The aim of this study was to describe the distribution of the different pathologic subtypes of IgG-associated glomerulopathy and to evaluate the IgG isotype involved in these diseases., Design, Setting, Participants, & Measurements: This was a retrospective study including all patients with glomerular deposits of monoclonal IgG referred to three nephrology departments between 1980 and 2008., Results: Twenty-six patients were included. Nephrotic syndrome was almost constantly associated with a renal dysfunction in 14 of 26 patients. The presence of M-spike was detected in only 30% of the patients, and an overt hematologic malignancy (myeloma, lymphoma) was identified in 9 of 26 patients. Patients were almost equally divided into two distinct histologic patterns: membranous nephropathy (MN) or membranoproliferative glomerulonephritis (MPGN). IgG3 deposits were identified in 80% of patients with MPGN, whereas IgG1 deposits were present in 64% of patients with MN. Ultrastructural study showed that immune deposits were nonorganized in most patients. Seven patients were treated with rituximab with excellent results: five of seven had a complete remission of the nephrotic syndrome and two of seven had a partial response. After a mean 24-month follow-up, only one patient experienced relapse of the nephropathy., Conclusions: GN with monoclonal Ig deposits can be associated with MPGN or MN, which are correlated with IgG3 and IgG1 isotypes, respectively. Rituximab appears to have a very favorable benefit-to-risk ratio for patients with no overt hematologic malignancy.

Background and Objectives: Kidney biopsy (KB), to date the only tool for the evaluation of renal fibrosis, carries specific risks, and its relevance is limited by the small size of renal parenchyma assessed. Thus, a noninvasive alternative to KB is required. Collagen type III amino-terminal propeptide (PIIINP) is a degradation product of collagen type III, the increase of which may reflect an ongoing fibrotic process., Design, Setting, Participants, & Measurements: In a prospective study including 199 patients with various stages of chronic kidney disease (CKD), the association between urinary PIIINP/creatinine ratio (UPIIINP/Cr), patients' characteristics, and renal fibrosis was assessed., Results: A total of 118 of the patients had UPIIINP/Cr measured simultaneously with the performance of a KB. In patients, median UPIIINP/Cr was 290 ng/mmol versus 93.7 ng/mmol in controls. In univariate analysis, UPIIINP/Cr was correlated with serum creatinine, estimated GFR, CKD stage, presence of coronary artery disease, and nephropathy type (glomerulonephritis versus other types). In multivariate analysis, only estimated GFR and nephropathy type were correlated with UPIIINP/Cr. UPIIINP/Cr was closely correlated with the extent of interstitial fibrosis in KB assessed using two different methods. Moreover, UPIIINP/Cr >800 ng/mmol had a negative predictive value of 94% to detect patients in whom KB will eventually prove "noninformative" (KB leading neither to a definite diagnosis of nephropathy nor to specific treatment)., Conclusions: UPIIINP/Cr is a promising fibro-test for the kidney and may alleviate the need for KB in some patients with CKD. Its predictive value for CKD progression deserves evaluation in prospective studies.

Background and Objectives: Cyst infection is a complex diagnostic and therapeutic issue in patients with autosomal dominant polycystic kidney disease (ADPKD); however, published data regarding the diagnosis and the management of cyst infections in patients with ADPKD are sparse., Design, Setting, Participants, & Measurements: A retrospective study was conducted in a referral center for patients with ADPKD in Paris, France. We identified using a computerized database all patients who had ADPKD and were admitted in the nephrology department of Hôpital Necker between January 1998 and August 2008 with likely or definite renal and/or hepatic cyst infection. Medical files of all included patients were reviewed., Results: Among 389 identified patients with ADPKD, 33 (8.4%) had 41 episodes of cyst infection, including eight definite and 33 likely cases. The incidence of cyst infections in patients with ADPKD was 0.01 episode per patient per year. Microbiological documentation was available for 31 episodes (75%), Escherichia coli accounting for 74% of all retrieved bacterial strains. Positron emission tomography scan proved superior to ultrasound, Computed tomography scan, and magnetic resonance imaging for the detection of infected cysts. Clinical efficacy of initial antibiotic treatment was noted in 71% of episodes. Antibiotic treatment modification was more frequently required for patients who were receiving initial monotherapy compared with those who were receiving bitherapy. Large (diameter >5 cm) infected cysts frequently required drainage., Conclusions: Positron emission tomography scan will probably make the diagnosis of cyst infections easier and more accurate. Antibiotic association, including a fluoroquinolone, and the drainage of large infected cysts remain the main treatment for cyst infections.

Background and Objectives: Clinically relevant kidney involvement is uncommonly described in adult patients with cystic fibrosis (CF). We sought to report on a series of patients with CF and kidney biopsy-documented renal involvement., Design, Setting, Participants, & Measurements: A retrospective study was undertaken in two referral centers for adult patients with CF in Paris, France. Patients who had undergone a biopsy of native kidneys between 1992 and 2008 were identified, and their medical records were reviewed., Results: We identified 13 adult patients with CF and renal disease. Proteinuria was present in all but two cases and was associated with progressive renal impairment in four patients (median serum creatinine 85 micromol/L; range 53 to 144 micromol/L). Renal biopsy disclosed a heterogeneous spectrum of nephropathies including AA amyloidosis (n = 3), diabetic glomerulopathy (n = 3), FSGS (n = 2), minimal-change disease (n = 1), postinfectious glomerulonephritis (n = 1), IgA nephropathy related to Henoch-Schönlein purpura (n = 1), membranous nephropathy (n = 1), and chronic interstitial nephropathy (n = 1). Chronic renal failure occurred in five patients, and one patient reached ESRD., Conclusions: Although rare, clinically significant renal disease may arise in young adult patients with CF. Given the wide spectrum of diseases that may be encountered, definite diagnosis by kidney biopsy is mandatory to optimize clinical treatment of these complex patients, particularly in the perspective of organ transplantation.

Background and Objectives: Standard treatment for lupus nephritis, including corticosteroids and cyclophosphamide, is efficient but is still associated with refractory or relapsing disease, or severe deleterious effects. Rituximab, a monoclonal chimeric anti-B cell antibody, is increasingly used in patients with lupus nephritis, but reported series were small and had a short follow-up., Design, Setting, Participants, & Measurements: The authors analyzed clinical and histologic data of 20 patients who were treated with rituximab for lupus nephritis and followed up for at least 12 mo., Results: Nineteen women and one man received rituximab as induction treatment for an active class IV (15 cases) or class V (5 cases) lupus nephritis. Rituximab was given for lupus nephritis refractory to standard treatment (12 cases), for relapsing disease (6 cases), or as first-line treatment (2 cases). Three patients received cyclophosphamide concomitantly with rituximab. Ten received new injections of rituximab as maintenance therapy. Side effects included mainly five infections and four moderate neutropenias. After a median follow-up of 22 mo, complete or partial renal remission was obtained in 12 patients (60%). Lupus nephritis relapsed in one patient, who responded to a new course of rituximab. The achievement of B cell depletion 1 mo after rituximab, which negatively correlated with black ethnicity and hypoalbuminemia, was strongly associated with renal response. Rapidly progressive glomerulonephritis did not respond to rituximab., Conclusion: Rituximab is an interesting therapeutic option in relapsing or refractory lupus nephritis when early B cell depletion is obtained.

Background and Objectives: Since the first description of pathology of the kidney in Waldenström disease in 1970, there have been few reports on kidney complications of IgM-secreting monoclonal proliferations. Here, we aimed to revisit the spectrum of renal lesions occurring in patients with a serum monoclonal IgM., Design, Setting, Participants, & Measurements: Fourteen patients with a circulating monoclonal IgM and a kidney disease related to B cell proliferation were identified retrospectively. Demographic, clinical, and laboratory data were assessed for each patient at the time of kidney biopsy., Results: Seven patients had a nephrotic syndrome. Patients without nephrotic syndrome all had impaired renal function. Mean serum creatinine was 238 micromol/L. For five patients, the diagnosis of monoclonal IgM preceded the kidney disease by 28.8 mo (range 12 to 60). Seven patients had Waldenström disease, two had a small B cell non-Hodgkin lymphoma, one had an IgM-excreting multiple myeloma, one had a marginal zone B cell lymphoma, and three had an IgM-related disorder. Renal lesions included (1) intracapillary monoclonal deposits disease with granular, electron-dense IgM thrombi occluding capillary lumens (5); (2) atypical membranoproliferative glomerulonephritis (3); (3) lambda light chain amyloidosis (2) associated with mu deposits in one patient; (4) acute tubular necrosis (1); and (5) CD20(+) lymphomatous infiltration (3). Remission of the nephrotic syndrome was attained in three of seven patients, and renal function improved after chemotherapy., Conclusions: Although renal complications of IgM proliferations are rare, a wide spectrum of kidney lesions is observed, without correlation with the type of hematologic disorder.

Background and Objectives: Light chain (AL) and secondary (AA) amyloidosis usually present as a systemic disease frequently involving the kidney and leading to ESRD. Data regarding patients with AA or AL amyloidosis undergoing dialysis remain scarce., Design, Setting, Participants, & Measurements: We retrospectively studied patients with AA or AL amyloidosis who started dialysis in five French centers between January 1, 1995 and December 31, 2005., Results: We identified 19 patients with AL and 20 patients with AA amyloidosis undergoing dialysis. Patients with AL amyloidosis had shorter time from diagnosis to dialysis (25.2 versus 69.3 mo, P < 0.05) and more extrarenal amyloidosis, especially cardiac (63.2 versus 5%, P < 0.0001). Mean duration of follow-up was 37.4 and 31.8 mo for patients with AL and AA amyloidosis, respectively. Fifteen patients (78.9%) with AL and three patients (15%) with AA amyloidosis died on dialysis. Median survival was shorter in patients with AL (26 mo) than AA amyloidosis [not definable (ND)] (P < 0.02). Sepsis and cardiac deaths were the main causes of mortality. Prognosis factors for death at 1 yr were AL type (P < 0.01), cardiac amyloidosis [odds ratio (OR) = 18, P < 0.01], heart failure (OR = 8, P < 0.04), and shorter time from diagnosis to dialysis (6.1 versus 56 mo, P < 0.03). Multivariate analysis indicated that AL type (P = 0.02), but not cardiac amyloidosis was independently associated with global mortality., Conclusions: Survival of patients with amyloidosis undergoing dialysis, especially AL type, is probably better than previously reported. However, mortality is higher in AL than AA type, especially in the setting of cardiac involvement.