A Novel Role for FERM Domain-Containing Protein 3 (FRMD3) in CKD.

BACKGROUND: Currently there are limited methods to link disease severity and risk of disease progression in Chronic Kidney Disease (CKD). To better understand this potential relationship, we interrogated the renal transcriptomic profile of individuals with CKD with measures of CKD severity and identified FERM-domain containing protein 3 (FRMD3) as a candidate gene for follow-up study. METHODS: RNA-seq was used to profile the transcriptome of CKD biopsies from the North Dublin Renal BioBank the results of which were correlated with clinical parameters. The potential function of FRMD3 was explored by interrogating the FRMD3 interactome and assessing the impact of lentiviral mediated FRMD3 knock down on human renal proximal tubule epithelial cells by assessing cell viability, metabolic activity, and structural markers. RESULTS: We identified a subset of 93 genes which are significantly correlated with estimated glomerular filtration rate and percentage tubulointerstitial fibrosis at time of biopsy and with CKD progression 5 years post-biopsy. These results were validated against transcriptomic data from an external cohort of 432 nephrectomy samples. One of the top-ranking genes from this subset, FRMD3, has previously been associated with the risk of developing diabetic kidney disease. Interrogating the interactome of FRMD3 in tubule epithelial cells revealed interactions with cytoskeletal components of cell-cell junctions. Knockdown of FRMD3 expression in tubule epithelial cells resulted in increased pro-apoptotic activity within the cells as well as dysregulation of E-Cadherin. CONCLUSIONS: We have identified a panel of kidney-specific transcripts correlated with severity and progression of kidney disease, and from this have identified a possible role for FRMD3 in tubule cell structure and health.

Kidney failure amongst Irish Travellers.

BACKGROUND: The occurrence of Kidney Failure with Replacement Therapy (KFRT) amongst Irish Travellers has not been well described. This study aims to determine the burden of KFRT amongst the Irish Traveller population and identify determinants of health amongst this cohort which may differ from the general population in Ireland. METHODS: This retrospective cohort study included self-identifying Irish Travellers with KFRT registered in the National Kidney Disease Clinical Patient Management System between 1995 and 2022. KFRT was defined as Chronic Kidney Disease stage 5 (CKD G5) treated by dialysis or CKD G1-G5 after transplantation. The primary outcome measure was the prevalence of KFRT in Irish Travellers. Secondary exploratory outcomes included age at diagnosis, family history, biopsy diagnosis, kidney replacement therapy (KRT) modality, time to initiation of KRT, primary vascular access used, and time to receive a kidney transplant. RESULTS: Four of six Irish hospital groups participated in the study. A total of 38 patients were identified as Irish Travellers with KFRT, with a crude prevalence rate of KFRT of 0.12% (CI 0.084-0.161, 95%) or 11.9 per 10,000 Irish Travellers. The mean age for diagnosis of kidney disease was 43 (SD, 20.8) and at commencement of KRT was 45 (SD, 20.9) years. A biopsy-proven diagnosis was provided in 24%. Twenty-two per cent was diagnosed with polycystic kidney disease or congenital anomalies of the kidney and urinary tract. The predominant modality for KRT was haemodialysis (89%), with central venous catheters being the most common initial vascular access (79%). Kidney transplants occurred in 45% of those studied, with a mean waiting time of 1.96 (SD, 1.6) years. CONCLUSIONS: The Irish Traveller community have similar prevalence of KFRT when compared to the national prevalence, with a short time interval from diagnosis to commencement of KRT. They are less likely to avail of home therapies but have comparable wait times to the national waiting time to receive a kidney transplant.

Native nephrectomies in patients with autosomal dominant polycystic kidney disease: retrospective cohort study.

BACKGROUND: Approximately 1 in 5 patients with autosomal dominant polycystic kidney disease (ADPKD) will undergo a native nephrectomy in their lifetime. These can be emergent or planned and the indications can range from space for kidney transplant, pain, hematuria and frequent urinary tract infections (UTIs). Due to the diverse nature of presentations, there is a lack of certainty about outcomes and optimal management. AIMS: This study aimed to evaluate preoperative indications and perioperative/postoperative complications in this patient cohort. METHODS: This retrospective review included 41 patients with ADPKD who underwent unilateral or bilateral nephrectomy in a single hospital between 2010 and 2020. We collected data on patient demographics, surgical indications, histological results and postoperative complications. We sourced this information using the hospital's patient medical records. RESULTS: The main indications for nephrectomy were pain (39.5%) and bleeding (41.8%). Further indications included recurrent UTIs (16.3%), space for transplantation (27.9%), query malignancy (4.7%) and compressive gastropathy (2.3%). With regard to side, 55.8% were right-sided, 23.3% were left-sided, and 20.9% were bilateral. Seven percent of nephrectomy specimens demonstrated malignancy. Postoperative morbidity included requiring blood transfusion and long hospital stay. Thirty-seven percent of patients received a postoperative blood transfusion. There was no immediate or postoperative mortality associated with any of the cases reviewed. CONCLUSIONS: In conclusion, this study demonstrates that native nephrectomy remains a safe operation for patients with ADPKD. Although further research is needed into, transfusion protocols, adjunctive therapies, such as TAE and research into timing of nephrectomy are still needed.

Adult presentation of a rare mitochondrial tRNA Val gene mutation-an expanding clinical phenotype.

BACKGROUND AND PURPOSE: Late-onset mitochondrial disorders are diagnostically challenging with significant heterogeneity in disease presentation. A case is reported of a 67-year-old gentleman who presented with a 3-month history of seizures, recurrent encephalopathy, ataxia and weight loss, preceded by recent initiation of haemodialysis for end-stage chronic kidney disease. METHODS: Extensive work-up including serological, cerebrospinal fluid, magnetic resonance imaging and electroencephalography was performed. Whole exome sequencing and muscle biopsy confirmed the diagnosis. RESULTS: Magnetic resonance imaging brain demonstrated a single non-enhancing T2 fluid attenuated inversion recovery hyperintense cortical/subcortical signal change in the right temporal lobe and cerebellar atrophy. Given the subacute presentation of uncertain aetiology, he was empirically treated for autoimmune/paraneoplastic encephalitis. Despite radiological resolution of the cortical abnormality 2 weeks later, there was no clinical improvement. Further collateral history unveiled a mildly ataxic gait and longstanding hearing loss suggestive of a genetic cause. Whole exome sequencing revealed a likely pathogenic, heteroplasmic mitochondrial DNA variant in the MT-TV gene, m.1659T>C, present at higher levels of heteroplasmy in muscle (91%) compared to other mitotic tissues. A high fat/protein diet and multivitamins including co-enzyme Q10 were commenced. Treatment of the nutritional deficiency and avoidance of intermittent fasting due to unreliable oral intake secondary to encephalopathy probably contributed to the clinical improvement seen over the ensuing few months, with resolution of his encephalopathy and return to his baseline gait and weight. CONCLUSION: An adult case is reported with an acute neurological presentation mimicking encephalitis, caused by a heteroplasmic m.1659T>C MT-TV variant, previously reported once in a child who displayed a different clinical phenotype.

Long-term renal function following radical cystectomy and ileal conduit creation.

BACKGROUND: Treatment for bladder cancer includes radical cystectomy (RC) and urinary diversion; RC is associated with long-term morbidity, kidney impairment and mortality. AIM: To identify risk factors associated with postoperative long-term kidney function and mortality. METHODS: Retrospective study of patients with RC and urinary diversion in Beaumont Hospital from 1996 to 2016. We included patients who had follow-up at least 2 years post-procedure. We assessed estimated glomerular filtration rate (eGFR) preoperatively and yearly post-procedure, dialysis commencement and mortality. Cox and Fine-Gray regression analyses were applied; p-value < 0.05 was considered significant. RESULTS: We included 264 patients, median age 68.3 years, 73.7% males. The most common diagnosis was bladder cancer 93.3%, TNM stages T ≥ 2 75.9%, N ≥ 1 47.6% and M1 28%. The median eGFR preoperative was 65.8 ml/min/1.73m2 and after 2 years 58.2 ml/min/1.73m2 (p: 0.009); 5.3% required chronic dialysis and 32.8% had a decrease > 10 ml/min/1.73m2. Risk factors associated with ESKD and start dialysis included younger age (HR: 0.90, CI 95% 0.87-0.94) and lower pre-operative eGFR (HR: 0.97, CI 95% 0.94-1.00). Overall mortality was 43.2% and 54.1% at 5 and 10 years, respectively; risk factors were older age (HR: 1.04, CI 95% 1.02-1.06), tumour stage T ≥ 2 (HR: 2.22, CI 95% 1.39-3.54) and no chemotherapy (HR: 1.72, CI 95% 1.18-2.51). Limitations include retrospective design, absence of control group and single centre experience. CONCLUSIONS: Patients with RC are at risk of progressive kidney function deterioration and elevated mortality and the main risk factors associated were age and preoperative eGFR. Regular monitoring of kidney function will permit early diagnosis and treatment.

High frequency and mortality of head and neck malignancy in organ transplant recipients in Ireland - A national cohort study.

BACKGROUND: Solid organ transplant recipients are recognized to carry a high burden of malignancy and frequently this cancer develops in the head and neck region. Furthermore, cancer of the head and neck post-transplant carries a significantly increased mortality. In this study, we aim to conduct a national retrospective cohort study to investigate the impact of head and neck cancer in terms of frequency and mortality in a large group of solid organ transplant recipients over a 20 year time span and compare the mortality in transplant patients to non-transplant patients with head and neck cancer. METHODS: Patients in the Republic of Ireland who underwent solid organ transplantation between 1994 and 2014 who developed post-transplant head and neck malignancy were identified from the records of two prospective, national databases (National Cancer Registry of Ireland (NCRI) and The Irish Transplant Cancer Group database) working in conjunction with each other. Incidence of head and neck malignancy post-transplant was compared with the general population by means of standardised incidence ratios (SIR). Cumulative incidence of all cause and cancer related mortality from head and neck keratinocytic was undertaken by a competing risks analysis. RESULTS: A total of 3346 solid organ transplant recipients were identified, 2382 (71.2 %) kidney, 562 (16.8 %) liver, 214 (6.4 %) cardiac and 188 (5.6 %) lung. During the period of follow up of 428 patients developed head and neck cancer, representing (12.8 %) of the population. 97 % of these patients developed keratinocytic cancers, specifically, of head and neck. The frequency of post-transplant head and neck cancer was related to the duration of immunosuppression with 14 % of patients developing cancer at 10 years and 20 % having developed at least one cancer by 15 years. 12 (3 %) patients developed non-cutaneous head and neck malignancy. 10 (0.3 %) patients died due to head and neck keratinocytic malignancy post-transplant. Competing risk analysis demonstrated that organ transplantation conferred a strong independent effect of death, compared to non-transplant patients with head and neck keratinocytes. This applied specifically for kidney (HR 4.4, 95 % CI 2.5-7.8) and heart transplants (HR 6.5, 95 % CI 2.1-19.9), and overall, across the four transplant categories (P < 0.001). The SIR of developing keratinocyte cancer varied based on primary tumor site, gender, and type of transplant organ. CONCLUSION: Transplant patients demonstrate a particularly high rate of head and neck keratinocyte cancer with a very high rate of associated mortality. Physicians should be cognizant of the increased rate of malignancy in this population and monitor for red flag signs/symptoms.

Rare disease gene association discovery from burden analysis of the 100,000 Genomes Project data.

To discover rare disease-gene associations, we developed a gene burden analytical framework and applied it to rare, protein-coding variants from whole genome sequencing of 35,008 cases with rare diseases and their family members recruited to the 100,000 Genomes Project (100KGP). Following in silico triaging of the results, 88 novel associations were identified including 38 with existing experimental evidence. We have published the confirmation of one of these associations, hereditary ataxia with UCHL1 , and independent confirmatory evidence has recently been published for four more. We highlight a further seven compelling associations: hypertrophic cardiomyopathy with DYSF and SLC4A3 where both genes show high/specific heart expression and existing associations to skeletal dystrophies or short QT syndrome respectively; monogenic diabetes with UNC13A with a known role in the regulation of ß cells and a mouse model with impaired glucose tolerance; epilepsy with KCNQ1 where a mouse model shows seizures and the existing long QT syndrome association may be linked; early onset Parkinson's disease with RYR1 with existing links to tremor pathophysiology and a mouse model with neurological phenotypes; anterior segment ocular abnormalities associated with POMK showing expression in corneal cells and with a zebrafish model with developmental ocular abnormalities; and cystic kidney disease with COL4A3 showing high renal expression and prior evidence for a digenic or modifying role in renal disease. Confirmation of all 88 associations would lead to potential diagnoses in 456 molecularly undiagnosed cases within the 100KGP, as well as other rare disease patients worldwide, highlighting the clinical impact of a large-scale statistical approach to rare disease gene discovery.

Persistent DNA damage underlies tubular cell polyploidization and progression to chronic kidney disease in kidneys deficient in the DNA repair protein FAN1.

Defective DNA repair pathways contribute to the development of chronic kidney disease (CKD) in humans. However, the molecular mechanisms underlying DNA damage-induced CKD pathogenesis are not well understood. Here, we investigated the role of tubular cell DNA damage in the pathogenesis of CKD using mice in which the DNA repair protein Fan1 was knocked out. The phenotype of these mice is orthologous to the human DNA damage syndrome, karyomegalic interstitial nephritis (KIN). Inactivation of Fan1 in kidney proximal tubule cells sensitized the kidneys to genotoxic and obstructive injury characterized by replication stress and persistent DNA damage response activity. Accumulation of DNA damage in Fan1 tubular cells induced epithelial dedifferentiation and tubular injury. Characteristic to KIN, cells with chronic DNA damage failed to complete mitosis and underwent polyploidization. In vitro and in vivo studies showed that polyploidization was caused by the overexpression of DNA replication factors CDT1 and CDC6 in FAN1 deficient cells. Mechanistically, inhibiting DNA replication with Roscovitine reduced tubular injury, blocked the development of KIN and mitigated kidney function in these Fan1 knockout mice. Thus, our data delineate a mechanistic pathway by which persistent DNA damage in the kidney tubular cells leads to kidney injury and development of CKD. Furthermore, therapeutic modulation of cell cycle activity may provide an opportunity to mitigate the DNA damage response induced CKD progression.

Complexities in diagnosing and treating endophthalmitis in the post stem cell transplant setting.

Endophthalmitis is a rare but sight-threatening manifestation of systemic infection. Immunosuppression is a well-recognised risk factor for development of endophthalmitis. Determining the aetiology can be complex, particularly in the context of immunosuppression, we present the diagnostic and treatment dilemmas associated with a patient who complains of blurred vision 2 weeks following an allogeneic stem cell transplant for refractory Hodgkin's disease. We demonstrate that in the context of immunosuppression post stem cell transplantation, a broad differential should be maintained until a microbiological diagnosis can be confirmed. In particular, we evaluate how clinical suspicion can diverge from typical fundoscopic findings in the diagnosis of endophthalmitis.

The utility of a genetic kidney disease clinic employing a broad range of genomic testing platforms: experience of the Irish Kidney Gene Project.

BACKGROUND AND AIMS: Genetic testing presents a unique opportunity for diagnosis and management of genetic kidney diseases (GKD). Here, we describe the clinical utility and valuable impact of a specialized GKD clinic, which uses a variety of genomic sequencing strategies. METHODS: In this prospective cohort study, we undertook genetic testing in adults with suspected GKD according to prespecified criteria. Over 7 years, patients were referred from tertiary centres across Ireland to an academic medical centre as part of the Irish Kidney Gene Project. RESULTS: Among 677 patients, the mean age was of 37.2 ± 13 years, and 73.9% of the patients had family history of chronic kidney disease (CKD). We achieved a molecular diagnostic rate of 50.9%. Four genes accounted for more than 70% of identified pathogenic variants: PKD1 and PKD2 (n = 186, 53.4%), MUC1 (8.9%), and COL4A5 (8.3%). In 162 patients with a genetic diagnosis, excluding PKD1/PKD2, the a priori diagnosis was confirmed in 58% and in 13% the diagnosis was reclassified. A genetic diagnosis was established in 22 (29.7%) patients with CKD of uncertain aetiology. Based on genetic testing, a diagnostic kidney biopsy was unnecessary in 13 (8%) patients. Presence of family history of CKD and the underlying a priori diagnosis were independent predictors (P < 0.001) of a positive genetic diagnosis. CONCLUSIONS: A dedicated GKD clinic is a valuable resource, and its implementation of various genomic strategies has resulted in a direct, demonstrable clinical and therapeutic benefits to affected patients.

Monoallelic IFT140 pathogenic variants are an important cause of the autosomal dominant polycystic kidney-spectrum phenotype.

Autosomal dominant polycystic kidney disease (ADPKD), characterized by progressive cyst formation/expansion, results in enlarged kidneys and often end stage kidney disease. ADPKD is genetically heterogeneous; PKD1 and PKD2 are the common loci (∼78% and ∼15% of families) and GANAB, DNAJB11, and ALG9 are minor genes. PKD is a ciliary-associated disease, a ciliopathy, and many syndromic ciliopathies have a PKD phenotype. In a multi-cohort/-site collaboration, we screened ADPKD-diagnosed families that were naive to genetic testing (n = 834) or for whom no PKD1 and PKD2 pathogenic variants had been identified (n = 381) with a PKD targeted next-generation sequencing panel (tNGS; n = 1,186) or whole-exome sequencing (WES; n = 29). We identified monoallelic IFT140 loss-of-function (LoF) variants in 12 multiplex families and 26 singletons (1.9% of naive families). IFT140 is a core component of the intraflagellar transport-complex A, responsible for retrograde ciliary trafficking and ciliary entry of membrane proteins; bi-allelic IFT140 variants cause the syndromic ciliopathy, short-rib thoracic dysplasia (SRTD9). The distinctive monoallelic phenotype is mild PKD with large cysts, limited kidney insufficiency, and few liver cysts. Analyses of the cystic kidney disease probands of Genomics England 100K showed that 2.1% had IFT140 LoF variants. Analysis of the UK Biobank cystic kidney disease group showed probands with IFT140 LoF variants as the third most common group, after PKD1 and PKD2. The proximity of IFT140 to PKD1 (∼0.5 Mb) in 16p13.3 can cause diagnostic confusion, and PKD1 variants could modify the IFT140 phenotype. Importantly, our studies link a ciliary structural protein to the ADPKD spectrum.

Lessons Learned From a Case of Behcet's Disease Presenting With Fever and Life-Threatening Venous Thromboembolism.

Infection mimics pose a challenge in the world of infectious diseases. Fever of unknown origin (FUO) requires careful consideration for a broad range of diagnoses. The answer often lies in a careful history and dedicated clinical examination. A delay in diagnosis can result in greater morbidity for the patient. We present the diagnostic challenges in a patient with an infection mimic, Behcet's disease (BD), who presented with recurrent venous thromboembolism (VTE) and fever of unknown origin (FUO). We present the case of a 53-year-old male of Irish Caucasian ethnicity who presented with a history of fevers and recurrent VTE at a university hospital in Dublin, Ireland. Past medical history includes schistosomiasis, which was treated following a trip to sub-Saharan Africa. Our patient was previously diagnosed with a provoked deep vein thrombosis (DVT). He went on to experience four subsequent episodes of VTE, including DVT, pulmonary embolism (PE), and cerebral venous sinus thrombosis (CVST) while on different forms of anticoagulation. On each of these occasions, there was a concern for sepsis due to fevers > 38°C and a C-reactive protein (CRP) > 200 mg/L. The infection workup included routine laboratory tests, blood and urine cultures, CT of the abdomen and pelvis (CTAP), echocardiogram, and PET-CT, all of which were unrevealing. However, a focused clinical examination revealed evidence of subtle scrotal and oral ulceration, pustulation, and erythema at several sites in his upper limb following venesection and cannulation. In this context, a diagnosis of Behcet's disease was considered. A diagnosis of Behcet's disease can only be confidently made after the exclusion of other potential etiologies. In this case, we had to consider a broad range of infectious (malaria, schistosomiasis, rickettsial disease, and endocarditis) and noninfectious (malignancy, antiphospholipid syndrome (APS), myeloproliferative disorders, and paroxysmal nocturnal hemoglobinuria (PNH)) diseases. A delay in diagnosis comes at the cost of increased morbidity and mortality for the patient. A detailed history and clinical examination are key, in addition to a high index of suspicion. Following the induction of high-dose steroid, our patient is doing very well on maintenance adalimumab. From an anticoagulation perspective, he is warfarinized and has not had any further episodes of VTE.

Understanding Incoming Canadian and US Veterinary Students' Attitudes and Perceptions of Their Dietary Habits and Levels of Physical Activity.

As critical components of individual well-being, nutrition and physical activity have important physical and psychological implications. Veterinary students face demanding schedules and potentially high rates of psychological distress. Though veterinary students' strategies for healthy eating have been explored, factors influencing their ability to achieve a healthy diet are less understood. This study assesses incoming veterinary students' perceived attitudes to their dietary habits and physical activity levels. Incoming students (n = 322) at five Canadian and five randomly selected US veterinary schools completed a questionnaire inquiring about demographic information, dietary attitudes and habits, and activity levels. More than half (58%) of students perceived their diet to be moderately healthy. A desire to feel better and have more energy was the most reported (79%) motivating factor to modifying personal eating habits and was significantly associated with improved odds of having a perceived healthy diet (OR = 2.22, p < .024). A busy lifestyle was perceived as a barrier to changing current eating habits by 92% of respondents. Students reporting a desire to maintain their health (OR = 3.42, p < .001) and moderate (OR = 2.81, p < .003) or high (OR = 2.30, p < .044) routine physical activity levels were also more likely to perceive their diet as healthy. Findings show that incoming veterinary students' perceptions may influence their goals of achieving a healthy lifestyle. An understanding of incoming veterinary students' barriers and motivators could be applied in future research to assist students in achieving personalized goals.

The genetic landscape of polycystic kidney disease in Ireland.

Polycystic kidney diseases (PKDs) comprise the most common Mendelian forms of renal disease. It is characterised by the development of fluid-filled renal cysts, causing progressive loss of kidney function, culminating in the need for renal replacement therapy or kidney transplant. Ireland represents a valuable region for the genetic study of PKD, as family sizes are traditionally large and the population relatively homogenous. Studying a cohort of 169 patients, we describe the genetic landscape of PKD in Ireland for the first time, compare the clinical features of patients with and without a molecular diagnosis and correlate disease severity with autosomal dominant pathogenic variant type. Using a combination of molecular genetic tools, including targeted next-generation sequencing, we report diagnostic rates of 71-83% in Irish PKD patients, depending on which variant classification guidelines are used (ACMG or Mayo clinic respectively). We have catalogued a spectrum of Irish autosomal dominant PKD pathogenic variants including 36 novel variants. We illustrate how apparently unrelated individuals carrying the same autosomal dominant pathogenic variant are highly likely to have inherited that variant from a common ancestor. We highlight issues surrounding the implementation of the ACMG guidelines for variant pathogenicity interpretation in PKD, which have important implications for clinical genetics.

Integration of genetic and histopathology data in interpretation of kidney disease.

For many years renal biopsy has been the gold standard for diagnosis in many forms of kidney disease. It provides rapid, accurate and clinically useful information in most individuals with kidney disease. However, in recent years, other diagnostic modalities have become available that may provide more detailed and specific diagnostic information in addition to, or instead of, renal biopsy. Genomics is one of these modalities. Previously prohibitively expensive and time consuming, it is now increasingly available and practical in a clinical setting for the diagnosis of inherited kidney disease. Inherited kidney disease is a significant cause of kidney disease, in both the adult and paediatric populations. While individual inherited kidney diseases are rare, together they represent a significant burden of disease. Because of the heterogenicity of inherited kidney disease, diagnosis and management can be a challenge and often multiple diagnostic modalities are needed to arrive at a diagnosis. We present updates in genomic medicine for renal disease, how genetic testing integrates with our knowledge of renal histopathology and how the two modalities may interact to enhance patient care.

Diagnostic utility of genetic testing in patients undergoing renal biopsy.

High-throughput DNA testing is becoming established as a standard diagnostic test in the renal clinic. Previously published studies on cohorts of patients with unexplained chronic kidney disease of a suspected genetic aetiology have suggested a diagnostic yield for genomic sequencing of up to 18%. Here we determine the yield of targeted gene panel in a clinically unscreened cohort of patients referred for percutaneous native renal biopsy. Patients who underwent renal biopsy for investigation of chronic kidney disease were sequenced using a genomic sequencing panel covering 227 genes in which variation is known to be associated with monogenic chronic kidney disease (CKD). Candidate disease-causing variants were assessed for pathogenicity using guidelines from the American College for Medical Genetics and Genomics. Fifty CKD patients were recruited and sequenced. A molecular diagnosis was obtained for two patients (4%). A molecular diagnosis is possible using genomic testing in ∼4% of clinically unscreened patients undergoing renal biopsy. Genetic screening may be useful for diagnosis in a subset of CKD patients but is most valuable when applied to patients with suspected heritable forms of kidney disease.

The impact of switching to mTOR inhibitor-based immunosuppression on long-term non-melanoma skin cancer incidence and renal function in kidney and liver transplant recipients.

Background: Solid organ transplantation is associated with increased risk of non-melanoma skin cancer. Studies with short follow up times have suggested a reduced occurrence of these cancers in recipients treated with mammalian target of rapamycin inhibitors as maintenance immunosuppression. We aimed to describe the occurrence of skin cancers in renal and liver transplant recipients switched from calcineurin inhibitor to sirolimus-based regimes.Methods: We performed a retrospective study of sirolimus conversion within the Irish national kidney and liver transplant programs. These data were linked with the National Cancer Registry Ireland to determine the incidence of NMSC among these recipients. The incidence rate ratio (IRR) for post versus pre-conversion NMSC rates are referred in this study as an effect size with [95% confidence interval].Results: Of 4,536 kidney transplants and 574 liver transplants functioning on the 1 January 1994 or transplanted between 1 January 1994 and 01 January 1994 and 01 January 2015, 85 kidney and 88 liver transplant recipients were transitioned to sirolimus-based immunosuppression. In renal transplants, the rate of NMSC was 131 per 1000 patient years pre-switch to sirolimus, and 68 per 1000 patient years post switch, with adjusted effect size of 0.48 [0.31 - 0.74] (p = .001) following the switch. For liver transplant recipients, the rate of NMSC was 64 per 1,000 patient years pre-switch and 30 per 1,000 patient years post switch, with an adjusted effect size of 0.49 [0.22 - 1.09] (p .081). Kidney transplant recipients were followed up for a median 3.4 years. Liver transplants were followed for a median 6.6 years.Conclusions: In this study, the conversion of maintenance immunosuppression from calcineurin inhibitors to mTOR inhibitors for clinical indications did appear to reduce the incidence of NMSC in kidney and liver transplant recipients.

Cancer survival in kidney transplant recipients in Ireland.

BACKGROUND: Transplantation is a well-known risk factor for malignancy. However, outcomes of cancer in transplant recipients compared with non-transplant recipients are less well studied. We aim to study the survival in kidney transplant recipients who develop cancer and compare this with cancer outcomes in the general population. METHODS: We linked data from the National Cancer Registry Ireland with the National Kidney Transplant Database. The period of observation was from 1 January 1994 until 31 December 2014. Transplant recipients were considered at risk from the time of diagnosing cancer. We administratively censored data at 10 years post-cancer diagnosis. Survival was compared with all patients in the general population that had a recorded diagnosis of cancer. RESULTS: There were 907 renal transplant recipients and 426679 individuals in the general population diagnosed with cancer between 1 January 1994 and 31 December 2014. In those with non-melanoma skin cancer, the hazard ratio (HR) for 10-year, all-cause mortality [HR = 3.06, 95% confidence interval (CI) 2.66-3.52] and cancer-specific mortality (HR = 3.91, 95% CI 2.57-5.96) was significantly higher among transplant recipients than the general population. Patients who developed non-Hodgkin lymphoma (HR = 2.89, 95% CI 1.96-4.25) and prostate cancer (HR = 4.32, 95% CI 2.39-7.82) had increased all-cause but not cancer-specific mortality. Colorectal, lung, breast and renal cell cancer did not show an increased risk of death in transplant recipients. CONCLUSION: Cancer-attributable mortality is higher in kidney transplant recipients with non-melanoma skin cancer compared with non-transplant patients. The American Joint Committee on Cancer staging should reflect the increased hazard of death in these immunosuppressed patients.

Polygenic risk score of non-melanoma skin cancer predicts post-transplant skin cancer across multiple organ types.

Polygenic risk scores (PRSs) calculated from genome-wide association studies (GWASs) of non-melanoma skin cancer (NMSC) in a general, non-transplant setting have recently been shown to predict risk of and time to post-renal transplant skin cancer. In this study, we set out to test these findings in a cohort of heart, lung, and liver transplant patients to see whether these scores could be applied across different organ transplant types. Using the PRS from Stapleton et al (2018), PRS was calculated for each sample across a European ancestry heart, lung, and liver transplant cohorts (n = 523) and tested as predictor of time to NMSC post-transplant. The top PRS, squamous cell carcinoma (SCC) pT1 x 10-5 , (n SNPs = 1953), SCC pT1 x 10-6 , and SCC pT1 x 10-6 (n SNPs = 1061) were significantly predictive in the time to NMSC, SCC, and basal cell carcinoma (BCC) analysis across organ (P = .006, .02, and .02, respectively). We observed here a similar direction of effect and effect size [NMSC HR = 1.31(1.08-1.59)] to that in the original discovery study with increased polygenic burden leading to a faster time to developing NMSC. In summary, we found that PRS of NMSC calculated from GWAS of NMSC in non-transplant populations independently replicated in this cohort of heart, lung, and liver transplant.