Clinical Significance of the Cystic Phenotype in Alport Syndrome

RATIONALE & OBJECTIVE

Alport Syndrome (AS) is the most common genetic glomerular disease caused by mutations that affect Type IV collagen. However, the clinical characteristics and significance of AS with kidney cysts are not well defined. This study investigated the prevalence and clinical significance of cystic kidney phenotype in AS.

STUDY DESIGN

Retrospective cohort study.

SETTING

& Participants: One hundred-eight patients with AS and a comparison cohort of 79 patients with IgA Nephropathy (IgAN). Clinical, genetic, and imaging data were collected from medical records.

EXPOSURES

Cystic kidney phenotype evaluated by ultrasonography and defined as the presence of ≥3 cysts in each kidney. Demographic characteristics and eGFR at disease onset.

OUTCOMES

Cystic kidney phenotype in the AS and IgAN cohorts. Time to CKD stage 3b and longitudinal changes in eGFR in the AS cohort.

ANALYTICAL APPROACH

Logistic regression analysis to test independent strengths of associations of clinical/demographic features with the binary outcome of cystic phenotype. Survival analysis for the outcome of reaching CKD stage 3b and linear mixed models for changes in eGFR over time in the AS cohort.

RESULTS

We studied 108 patients with AS; 76 (70%) had genetic diagnosis. Autosomal dominant AS was prevalent, accounting for 68% of patients with genetic diagnosis. Cystic kidney phenotype was observed in 38% of patients with AS and was associated with normal sized kidneys in all but 3 patients, who showed increased total kidney volume, mimicking autosomal dominant polycystic kidney disease (ADPKD). The prevalence of cystic kidney phenotype was significantly higher in patients with AS when compared to comparison group of patients with IgAN (42% vs 19%; p=0.002). Patients with cystic kidney phenotype were older and had more marked reductions in eGFR than patients without cystic changes. Among patients with AS, the cystic phenotype was associated with older age and a faster decline eGFR.

LIMITATIONS

Retrospective, single-center study.

CONCLUSIONS

Cystic kidney phenotype is a common finding in AS. The cystic kidney phenotype is a common finding in AS suggesting a possible role in cystogenesis for the genetic variants that cause this disease.

Monoallelic pathogenic IFT140 variants are a common cause of autosomal dominant polycystic kidney disease-spectrum phenotype

Background

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disorder, characterized by development and enlargement of kidney cysts, eventually leading to end-stage kidney disease (ESKD). Pathogenic variants in the PKD1 and PKD2 genes are the major cause of ADPKD; additional rare variants in the GANAB, DNAJB11, ALG5 and ALG9 genes have been found in a minority of ADPKD patients. More recently, a significant number of ADPKD families have been linked to monoallelic variants in the IFT140 gene.

Methods

In this retrospective study, we tested the prevalence of the known causative genes of ADPKD-spectrum phenotype, including the PKD1, PKD2, GANAB, DNAJB11, ALG5, ALG and IFT140 genes, in a cohort of 129 ADPKD patients who consecutively underwent genetic testing in a single centre in Italy. Genetic testing utilized a combination of targeted next-generation sequencing, long-range polymerase chain reaction, Sanger sequencing and multiplex ligation-dependent probe amplification. Clinical evaluation was conducted through renal function testing and imaging features, including ultrasonography, computer tomography and magnetic resonance imaging.

Results

Of the 129 enrolled patients, 86 (66.7%) had pathogenic variants in PKD1 and 28 (21.7%) in PKD2, loss of function pathogenic variants in the IFT140 gene were found in 3 unrelated patients (2.3%), no pathogenic variants were found in other ADPKD genes and 12 patients (9.3%) remained genetically unresolved (ADPKD-GUR). Familial clinical and genetic screening of the index patients with ADPKD due to an IFT140 pathogenic variant (ADPKD-IFT140) allowed identification of eight additional affected relatives. In the 11 ADPKD-IFT140 patients, the renal phenotype was characterized by mild and late-onset PKD, with large renal cysts and limited kidney insufficiency. Extrarenal manifestations, including liver cysts, were rarely seen.

Conclusion

Our data suggest the monoallelic pathogenic IFT140 variants are the third most common cause of the ADPKD-spectrum phenotype in Italy, usually associated with a mild and atypical renal cystic disease.

Effect of Migalastat on cArdiac InvOlvement in FabRry DiseAse: MAIORA study

BACKGROUND

A small but significant reduction in left ventricular (LV) mass after 18 months of migalastat treatment has been reported in Fabry disease (FD). This study aimed to assess the effect of migalastat on FD cardiac involvement, combining LV morphology and tissue characterisation by cardiac magnetic resonance (CMR) with cardiopulmonary exercise testing (CPET).

METHODS

Sixteen treatment-naïve patients with FD (4 women, 46.4±16.2 years) with cardiac involvement (reduced T1 values on CMR and/or LV hypertrophy) underwent ECG, echocardiogram, troponin T and NT-proBNP (N-Terminal prohormone of Brain Natriuretic Peptide) assay, CMR with T1 mapping, and CPET before and after 18 months of migalastat.

RESULTS

No change in LV mass was detected at 18 months compared to baseline (95.2 g/m2 (66.0-184.0) vs 99.0 g/m2 (69.0-121.0), p=0.55). Overall, there was an increase in septal T1 of borderline significance (870.0 ms (848-882) vs 860.0 ms (833.0-875.0), p=0.056). Functional capacity showed an increase in oxygen consumption (VO2) at anaerobic threshold (15.50 mL/kg/min (13.70-21.50) vs 14.50 mL/kg/min (11.70-18.95), p=0.02), and a trend towards an increase in percent predicted peak VO2 (72.0 (63.0-80.0) vs 69.0 (53.0-77.0), p=0.056) was observed. The subset of patients who showed an increase in T1 value and a reduction in LV mass (n=7, 1 female, age 40.5 (28.6-76.0)) was younger and at an earlier disease stage compared to the others, and also exhibited greater improvement in exercise tolerance.

CONCLUSION

In treatment-naïve FD patients with cardiac involvement, 18-month treatment with migalastat stabilised LV mass and was associated with a trend towards an improvement in exercise tolerance. A tendency to T1 increase was detected by CMR. The subset of patients who had significant benefits from the treatment showed an earlier cardiac disease compared to the others.

TRIAL REGISTRATION NUMBER

NCT03838237.

[ADPKD and intracranial aneurysms: indications for screening, follow-up and clinical management]

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent hereditary nephropathy and is the fourth most common cause for end-stage renal disease in Europe. ADPKD is a systemic disease; besides the typical renal involvement, characterized by progressive cyst expansion leading to massive enlargement and distortion of the kidney architecture and, ultimately, to end-stage renal disease, multiple extrarenal manifestations can be observed included cysts in other organs, diverticulosis, cardiac valvulopathies, abdominal and inguinal hernias, vascular anomalies. The rupture of an intracranial aneurysm is one of the most serious complications in ADPKD patients. Aim of this review is to provide useful indications for the clinician to define the risk of intracranial aneurysms in ADPKD population, to identify screening criteria (which patients to screen, how often and with which diagnostic methods), to estimate the risk of rupture of intracranial aneurysms, which may require intervention.

Effect of migalastat on cardiac involvement in Fabry disease: preliminary results from MAIORA study

Background

Fabry Disease (FD) is a rare X-linked lysosomal storage disorder. Since 2016, pharmacological chaperone Migalastat has been approved for treatment of FD patients with amenable mutations to stabilize defective forms of the enzyme α-galactosidase A. A small but significant reduction in left ventricular (LV) mass after 18 months of Migalastat treatment has been previously reported by echocardiography. However, an integrated assessment of the effect of Migalastat on cardiac involvement, combining LV morphology and tissue composition by CMR with exercise capacity by cardiopulmonary test, is lacking.

Purpose

To determine the effects of 18 month treatment with Migalastat on LV mass, native T1 value and functional capacity in naïve patients with genetically confirmed FD cardiomyopathy.

Methods

Sixteen treatment naïve FD patients (4 females, mean age 46.4±16.2) with amenable mutations and signs of cardiac involvement underwent CMR with T1 mapping and cardio-pulmonary testing before and after 18 months of migalastat therapy as a part of MAIORA Study. Cardiac involvement was defined as presence of reduced native T1 values at CMR (a surrogate of myocardial glycosphingolipid storage) and/or LV hypertrophy (LVH). Nine patients (56%, 2 females, mean age 56.4±12.7 years) had LVH at baseline.

Results

Migalastat treatment was well tolerated in all patients, with no serious adverse event. No change in LV mass was detected at 18 months compared to baseline (95.2 (66.0–184.0) vs 103.0 (71.0–182.0) g/m2; p=0.5516). The same result was found after stratifying patients according to presence/absence of Late Gadolinium Enhancement (LGE) (LGE+ n=8, 2 females, mean age 56.2±13.1 years). There was a trend towards an increased native septal T1 value (870.0 (848–882) vs 860.0 (833.0–875.0) ms at baseline; p 0.056) with unchanged extracellular volume (ECV) (0.26 (0.23–0.028) vs 0.26 (0.22–0.29) at baseline; p 0.276) in the overall cohort. An improvement in functional capacity with a trend towards an increase in percent-predicted peak VO2 (72.0 (61.25–80.75) vs 67.0 (45.2–79.2) at baseline; p 0.056) and a significant increase in VO2 at anaerobic threshold (14.8 (12.6–20.0) vs 13.10 (6.8–18.6) ml/kg/min at baseline; p 0.004) was reported in the total population.

Conclusion

In treatment naïve FD patients with amenable mutations and signs of early or overt cardiac involvement, 18-month treatment with Migalastat stabilized LV mass both in patients with and without LGE and was associated with an improvement in exercise tolerance. The trend towards an increase in T1 value associated with unchanged ECV suggests partial clearance of cardiomyocyte glycoshingolipid storage. These real-world data are consistent with a beneficial impact of migalastat on the progression of cardiac involvement in FD.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Amicus Therapeutics

Expanding the variability of the ADPKD-GANAB clinical phenotype in a family of Italian ancestry

BACKGROUND

Causative mutations in the GANAB gene have been described in only 14 families, 9 diagnosed with late-onset Autosomal Dominant Polycystic Kidney Disease (ADPKD) and 5 with Autosomal Dominant Polycystic Liver Disease (ADPLD).

CASE

Diagnosis of ADPKD was made in a 45-year old man during screening for hernia repair. CT scan showed enlarged cystic kidneys, nephrolithiasis and normal-sized liver with multiple cysts. Hematuria, hypertension and aortic root dilatation were also documented. Renal function was normal. Molecular analysis of PKD genes disclosed a heterozygous p.R839W GANAB variant inherited from the mother. Both his elderly parents presented normal-sized bilateral cystic kidneys but normal renal function. The GANAB-ADPKD mother had no liver cysts. The father was screened for PKD-related genes and no variant was found.

GENETIC ANALYSIS

We describe a new family with late-onset ADPKD due to the p.R839W GANAB variant, previously reported in a severe ADPLD patient, requiring liver transplantation.

DISCUSSION

Since ADPKD-GANAB is an ultrarare, recently described disease, reporting further patients may help unraveling gene-related phenotype. In our patients the p.R839W GANAB variant was not related to severe ADPLD, as previously reported, but with mild ADPKD and a plethora of renal and extrarenal manifestations, usually described in PKD1/PKD2 patients. The evidence that the GANAB variant may cause both ADPKD and ADPLD of variable severity supports that renal and hepatic cystogenesis are the result of a common defective polycystin-1 pathway.

Trabecular complexity as an early marker of cardiac involvement in Fabry disease

AIMS

Fabry cardiomyopathy is characterized by glycosphingolipid storage and increased myocardial trabeculation has also been demonstrated. This study aimed to explore by cardiac magnetic resonance whether myocardial trabecular complexity, quantified by endocardial border fractal analysis, tracks phenotype evolution in Fabry cardiomyopathy.

METHODS AND RESULTS

Study population included 20 healthy controls (12 males, age 32±9) and 45 Fabry patients divided into three groups: 15 left ventricular hypertrophy (LVH)-negative patients with normal T1 (5 males, age 28±13; Group 1); 15 LVH-negative patients with low T1 (9 males, age 33±9.6; Group 2); 15 LVH-positive patients (11 males, age 53.5±9.6; Group 3). Trabecular fractal dimensions (Dfs) (total, basal, mid-ventricular, and apical) were evaluated on cine images. Total Df was higher in all Fabry groups compared to controls, gradually increasing from controls to Group 3 (1.27±0.02 controls vs. 1.29±0.02 Group 1 vs. 1.30±0.02 Group 2 vs. 1.34±0.02 Group 3; P<0.001). Group 3 showed significantly higher values of all Dfs compared to the other Groups. Both basal and total Dfs were significantly higher in Group 1 compared with controls (basal: 1.30±0.03 vs. 1.26±0.04, P =0.010; total: 1.29±0.02 vs. 1.27±0.02, P=0.044). Total Df showed significant correlations with: (i) T1 value (r=-0.569; P<0.001); (ii) LV mass (r=0.664, P<0.001); (iii) trabecular mass (r=0.676; P <0.001); (iv) Mainz Severity Score Index (r=0.638; P<0.001).

CONCLUSION

Fabry cardiomyopathy is characterized by a progressive increase in Df of endocardial trabeculae together with shortening of T1 values. Myocardial trabeculation is increased before the presence of detectable sphingolipid storage, thus representing an early sign of cardiac involvement.

Kidney transplant patients with SARS-CoV-2 infection: The Brescia Renal COVID task force experience

The outcome of kidney transplant patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is still unclear. Here we describe the clinical characteristics, disease outcome, and risk factors for acute respiratory distress syndrome (ARDS) and death of a cohort of 53 kidney transplant patients with coronavirus disease 2019 (COVID-19). Eight of 53 have been handled as outpatients because of mild disease, on average with immunosuppression reduction and the addition of hydroxychloroquine and azithromycin; no patients required admission, developed ARDS, or died. Because of severe symptoms, 45/53 required admission: this cohort has been managed with immunosuppression withdrawal, methylprednisolone 16 mg/d, hydroxychloroquine, and antiviral drugs. Dexamethasone and tocilizumab were considered in case of ARDS. About 33% of the patients developed acute kidney injury, 60% ARDS, and 33% died. In this group, thrombocytopenia was associated to ARDS whereas lymphopenia at the baseline, higher D-dimer, and lack of C-reactive protein reduction were associated with risk of death. In the overall population, dyspnea was associated with the risk of ARDS and age older than 60 years and dyspnea were associated with the risk of death with only a trend toward an increased risk of death for patients on tacrolimus. In conclusion, SARS-CoV-2 infection may have a variable outcome in renal transplant patients, with higher risk of ARDS and death in the ones requiring admission.

Variable Expressivity of HNF1B Nephropathy, From Renal Cysts and Diabetes to Medullary Sponge Kidney Through Tubulo-interstitial Kidney Disease

Introduction

In humans, heterozygous mutations of hepatocyte nuclear factor 1beta (HNF1B) are responsible for a dominant inherited disease with both renal and extrarenal phenotypes. HNF1B nephropathy is the umbrella term that includes the various kidney phenotypes of the disease, ranging from congenital anomalies of the kidney and urinary tract (CAKUT), to tubular transport abnormalities, to chronic tubulointerstitial and cystic renal disease.

Methods

We describe 7 families containing 13 patients with ascertained HNF1B nephropathy. All patients underwent genetic testing and clinical, laboratory, and instrumental assessment, including renal imaging and evaluation of extrarenal HNF1B manifestations.

Results

Significant inter- and intrafamilial variability of HNF1B nephropathy has been observed. In our cohort, HNF1B pathogenic variants presented with renal cysts and diabetes syndrome (RCAD); renal cystic phenotype mimicking autosomal dominant polycystic kidney disease (ADPKD); autosomal dominant tubulointerstitial kidney disease (ADTKD) with or without hyperuricemia and gout; CAKUT; and nephrogenic diabetes insipidus (NDI). Of note, for the first time, we describe the occurrence of medullary sponge kidney (MSK) in a family harboring the HNF1B whole-gene deletion at chromosome 17q12. Genotype characterization led to the identification of an additional 6 novel HNF1B pathogenic variants, 3 frameshift, 2 missense, and 1 nonsense.

Conclusion

HNF1B nephropathy may present with a highly variable renal phenotype in adult patients. We expand the HNF1B renal clinical picture to include MSK as a potential new finding. Finally, we expand the allelic repertoire of the disease by adding novel HNF1B pathogenic variants.

A report from the Brescia Renal COVID Task Force on the clinical characteristics and short-term outcome of hemodialysis patients with SARS-CoV-2 infection

The SARS-CoV-2 epidemic is pressuring healthcare systems worldwide. Disease outcomes in certain subgroups of patients are still scarce, and data are needed. Therefore, we describe here the experience of four dialysis centers of the Brescia Renal COVID Task Force. During March 2020, within an overall population of 643 hemodialysis patients, SARS-CoV-2 RNA positivity was detected in 94 (15%). At disease diagnosis, 37 of the 94 (39%) patients (group 1) were managed on an outpatient basis, whereas the remaining 57 (61%) (group 2) required hospitalization. Choices regarding management strategy were made based on disease severity. In group 1, 41% received antivirals and 76% hydroxychloroquine. Eight percent died and 5% developed acute respiratory distress syndrome (ARDS). In group 2, 79% received antivirals and 77% hydroxychloroquine. Forty two percent died and 79% developed ARDS. Overall mortality rate for the entire cohort was 29%. History of ischemic cardiac disease, fever, older age (over age 70), and dyspnea at presentation were associated with the risk of developing ARDS, whereas fever, cough and a C-reactive protein higher than 50 mg/l at disease presentation were associated with the risk of death. Thus, in our population of hemodialysis patients with SARS-CoV-2 infection, we documented a wide range of disease severity. The risk of ARDS and death is significant for patients requiring hospital admission at disease diagnosis.

P0057ADPKD: COMPLEX GENOTYPES MAY EXPLAIN SEVERE PHENOTYPE AND INTRAFAMILIAL PHENOTYPIC VARIABILITY

Background and Aims

Discordant affected relative-pairs are seen in ∼10% of families with Autosomal Dominant Polycystic Kidney Disease (ADPKD); &lt;1% of patients exhibit very early onset (VEO) disease. Complex genotypes may result in renal disease variability beyond that predicted by the sole effect of a single PKD mutant allele, leading to the discovery of biallelic or digenic disease. Here we illustrate such complexity in 6 ADPKD pedigrees.

Method

Among our single-center ADPKD cohort (186 index patients), we selected pedigrees (P) in which marked familial phenotypic variability or severe and early onset disease was investigated by NGS and MLPA analysis of PKD1 and PKD2 genes and NGS analysis of other cystogenes. Segregation analysis by Sanger sequencing of PKD variants was performed in available affected and unaffected family members.

Results

In P1 and P2, the index cases (IC), presented with very early onset (VEO) disease characterized by prenatal/neonatal enlarged and hyperechogenic kidneys mimicking autosomal recessive polycystic kidney disease (ARPKD). In P1, with neonatal onset, the ADPKD affected father transmitted a PKD1 PT variant p.Gln4231*, whereas the mother, without renal cystic phenotype, transmitted a PKD1 hypomorphic variant p.Asp1332Asn.

In P2, the ADPKD-PKD2 mother’s pregnancy was complicated by Potter sequence. Parent’s PKHD1 gene analysis was negative. Two missense NT variants in PKD1/PKD2 genes were detected in the healthy father, respectively p.Gly1944Arg and p.Thr203Ile. Therefore, a complex PKD inheritance was supposed in the fetus. Fetus DNA was not available.

In P3 early onset (EO) ADPKD in two monozygous twins was underpinned by a PKD1 NT variant (p.Arg1951Gln) inherited by the ADPKD mild affected father and worsened by a de novo PKD1 truncating variant p.Arg2402*.

In P4 and P5 a digenic ADPKD (PKD1 +PKD2 and PKD1 +PKHD1) was diagnosed in severe ADPKD IC. In P4 the two most severely affected siblings carried a PKD2 T variant (p.Ala365fs) and a PKD1 NT variant p-Cys259Tyr.

In P5 the IC presented with EO ADPKD, a de novo splicing variant c.2097 + 5_+6insT in PKD1 gene was discovered but the phenotype was probably worsened by the presence of biallelic variant in a second cystogene PKHD1: one paternally inherited: p.Gly1712Arg and one maternally inherited: p.Asp3088Asn .

Elderly parents in P6 had mild ADPKD with bilateral few kidney cysts and preserved eGFR, whereas IC showed moderate/severe CKD due to ADPKD biallelic variants. The IC carried a homozygous PKD1 NT variant (p.Arg4154Cys): each mutant allele inherited from the mild ADPKD affected parents.

Conclusion

Our study illustrates the genetic complexity in an otherwise “simple” Mendelian disorder, providing insights into the genetic basis of severity of ADPKD cases and into ADPKD intrafamilial disease variability. In our pedigree all cases with more severe clinical picture in the family presented at least two PKD variants. In P5 we found for the first time an EO ADPKD due to both PKD1 and PKHD1 variants.

PKD1 and PKD2 sequence analysis together with cystic kidney disease gene panel analysis is recommended in those patients with discordant phenotype compared to family members. Molecular study of PKD patients is expected to be a good prognostic tool together with clinical and renal imaging data to better manage disease therapy, follow-up and reproductive issues.

A single center observational study of the clinical characteristics and short-term outcome of 20 kidney transplant patients admitted for SARS-CoV2 pneumonia

The outcome of SARS-CoV2 infection in patients who have received a kidney allograft and are being treated with immunosuppression is unclear. We describe 20 kidney transplant recipients (median age 59 years [inter quartile range 51-64 years], median age of transplant 13 years [9-20 years], baseline eGFR 36.5 [23-47.5]) with SARS-CoV2 induced pneumonia. At admission, all had immunosuppression withdrawn and were started on methylprednisolone 16 mg/day, all but one was commenced on antiviral therapy and hydroxychloroquine with doses adjusted for kidney function. At baseline, all patients presented fever but only one complained of difficulty in breathing. Half of patients showed chest radiographic evidence of bilateral infiltrates while the other half showed unilateral changes or no infiltrates. During a median follow-up of seven days, 87% experienced a radiological progression and among those 73% required escalation of oxygen therapy. Six patients developed acute kidney injury with one requiring hemodialysis. Six of 12 patients were treated with tocilizumab, a humanized monoclonal antibody to the IL-6 receptor. Overall, five kidney transplant recipients died after a median period of 15 days [15-19] from symptom onset. These preliminary findings describe a rapid clinical deterioration associated with chest radiographic deterioration and escalating oxygen requirement in renal transplant recipients with SARS-Cov2 pneumonia. Thus, in this limited cohort of long-term kidney transplant patients, SARS-CoV-2 induced pneumonia is characterized by high risk of progression and significant mortality.

P0074EXPANDING THE VARIABILITY OF THE ADPKD-GANAB CLINICAL PHENOTYPE: A NEW FAMILY OF ITALIAN ANCESTRY

Background and Aims

Causative GANAB mutations have been described in only 123 families, 98 diagnosed with late-onset mild ADPKD and 35 with ADPLD. We describe a new family with mild, late-onset ADPKD due to p. R839W GANAB mutation, previously reported in an ADPLD patient requiring liver transplantation.

Method

Mutation analysis of PKD1, PKD2, GANAB genes was performed by targeted NGS analysis. To analyze GANAB gene we developed a custom panel of 11 kidney cystogenes (GANAB, PKDH1, TSC1, TSC2, UMOD, HNF1B, REN, OFD1, PARN, DNAJB11, SEC61A1) designed using Ion Ampliseq Designer. Sanger sequencing was performed in order to validate all the variants classified as pathogenic, likely pathogenic and VUS. Raw sequence data analysis, including base calling, demultiplexing, alignment to the hg19 human reference genome, was performed using the Torrent Suite Software version 5.5; the average depth of total coverage was set at 500X and for variant calls at minimum of 30X. Deletion and duplication analysis of PKD1 and PKD2 was performed using MLPA P351-C1 and P352-D1 probemixes, MRC-Holland.

Results

Diagnosis of ADPKD was made in a 45-year old man during pre-surgical screening for umbilical and inguinal hernia repair. The patient's clinical course was characterized by several complications pertaining to the ADPKD spectrum: nephrolithiasis (20 yo); umbilical/bilateral inguinal hernia repair, hypertension and mild aortic root dilation (45 yo) and AKI due to ureteral obstruction (50 yo). Abdomen CT scan showed bilateral renal cysts (TKV 565 cc), nephrolithiasis, normal-sized liver with multiple cysts, and sigmoid colon diverticulosis. Renal function was normal (SCr 0.69 mg/dL, CKD-EPI 115 ml/min). In the index case, NGS and MLPA analysis of PKD1 and PKD2 genes did not detect variants. We then use the abovementioned multigene NGS panel and identified a missense heterozygous c.2515C&gt;T (p.R839W) variant in the GANAB gene. Screening was then extended to family members. No family members displayed renal function impairment. Both the 80 yo mother and the 84 yo father were found to have multiple bilateral kidney cysts (HtTKV of 239 ml and 435 ml, respectively), no liver cysts were found in either of them. Parents segregation analysis identified the GANAB variant p.R839W in the mother and in the maternal aunt. The father tested negative for all the abovementioned cystogenes.

Conclusion

we confirm that the renal phenotype caused by mutations in GANAB is very different from those due to mutations in PKD1 and PKD2, giving rise to a mild form of renal cystic disease, usually not progressing to ESRD. Despite the mild renal cystic burden, the index case showed a plethora of renal and extrarenal manifestations of ADPKD. The finding that patients with GANAB mutation can present with renal and liver cystic phenotype is intriguing, indicating a commonality between pathogenic background of two different inherited disorders, ADPKD and ADPLD. The missense GANAB mutation identified in our ADPKD family was first described in a pedigree reported by Porath et al. and diagnosed as ADPLD. This suggests that, beyond the effect of the shared mutation on GII subunit α, other modifier loci and environmental factors may influence the course of liver disease development and progression. Our study illustrates the important diagnostic role of a broader genetic testing, able to screen not only for PKD1 and PKD2 variants, but also for pathogenic variants in other cystogenes.

Management of Patients on Dialysis and With Kidney Transplantation During the SARS-CoV-2 (COVID-19) Pandemic in Brescia, Italy

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as coronavirus disease (COVID-19), is a major pandemic challenging health care systems around the world. The optimal management of patients infected with COVID-19 is still unclear, although the consensus is moving toward the need of a biphasic approach. During the first phase of the disease (from onset of the symptoms up to 7-10 days) viral-induced effects are prominent, with the opportunity to institute antiviral therapy. In the second inflammatory phase of the disease, immunosuppressive strategies (for example with glucocorticoids or anticytokine drugs) may be considered. This latter stage is characterized by the development of progressive lung involvement with increasing oxygen requirements and occasionally signs of the hemophagocytic syndrome. The management of the disease in patients with kidney disease is even more challenging, especially in those who are immunosuppressed or with severe comorbidities. Here we present the therapeutic approach used in Brescia (Italy) for managing patients infected with COVID-19 who underwent kidney transplantation and are receiving hemodialysis. Furthermore, we provide some clinical and physiopathological background, as well as preliminary outcome data of our cohort, to better clarify the pathogenesis of the disease and clinical management.

[Managing patients in dialysis and with kidney transplant infected with Covid-19]

We are in the midst of a health emergency that is totally new for us all and that requires a concerted effort, especially when it comes to safeguarding patients on hemodialysis, and kidney transplant recipients. Brescia is currently a very active cluster of infections (2918 cases on the 17/03/2020), second only to Bergamo. The way our structure is organised has allowed us to treat nephropathic patients directly within the Nephrology Unit, following of course a great deal of reshuffling; at the moment, we are treating 21 transplanted patients and 17 on hemodialysis. This has led us to adopt a systematic approach to handling this emergency, not only in managing inpatients, but also in researching the new disease. Our approach is mirrored in the guidelines attached to this article, originally intended for internal use only but potentially very useful to our colleagues, as they face the same exact problems. We have also started collecting data on our positive patients with the aim of understanding better the functioning of this disease and how best to manage it. If anyone is interested, we ask you to please get in touch with us, so we can coordinate our efforts.

High-Dose Melphalan and Stem Cell Transplantation in Patients on Dialysis Due to Immunoglobulin Light-Chain Amyloidosis and Monoclonal Immunoglobulin Deposition Disease

The kidney is the most common organ affected by immunoglobulin light-chain (AL) amyloidosis and monoclonal immunoglobulin deposition disease (MIDD), often leading to end-stage renal disease (ESRD). High-dose melphalan and stem cell transplantation (HDM/SCT) is effective for selected patients with AL amyloidosis, with high rates of complete hematologic response and potential for improved organ dysfunction. Data on tolerability and response to HDM/SCT in patients with ESRD due to AL amyloidosis and MIDD are limited. We analyzed data on toxicity, efficacy, and hematologic and renal response of HDM/SCT in 32 patients with AL amyloidosis and 4 patients with MIDD who were dialysis-dependent for ESRD treated at Boston Medical Center between 1994 and 2016. The most common grade 3/4 nonhematologic toxicities were infections (75%), metabolic abnormalities (56%), mucositis (42%), constitutional symptoms (39%), pulmonary complications (39%), and diarrhea (28%). Treatment related mortality (defined as death within 100 days of SCT) occurred in 8% (3 of 36). A complete hematologic response was achieved in 70% of evaluable patients (19 of 27) at 1 year after HDM/SCT. In the entire cohort, median overall survival (OS) after HDM/SCT was 5.8 years; median OS was 1 year for those who did not achieve a complete hematologic response and 8 years for those who did achieve a complete hematologic response. Twelve patients (33%) underwent kidney transplantation after successful treatment with HDM/SCT at a median of 2.4 years after SCT. HDM/SCT is safe and effective in inducing hematologic complete responses and prolonging survival in patients with ESRD from AL amyloidosis and MIDD. Achievement of a durable hematologic response can make these patients possible candidates for renal transplantation.