Since it was first described more than 50 years ago, recurrence of FSGS in kidney allografts has frustrated the transplant community. This rare condition is associated with considerable morbidity, ...and it is the most common cause of graft loss in patients with CKD stage 5 due to FSGS. However, the problem remains insufficiently studied. It is an ultra-orphan disease and incidence rates at individual centers are often very low and unpredictable. The published literature contains conflicting reports in basic epidemiologic data. Progress in defining the mechanisms of disease and advancing therapeutic options has been limited. The treatment options that are currently available are limited and largely ineffective. The range in time to recurrence and variability in responsiveness to treatment suggest that recurrence is not a single entity, but rather multiple phenotypes resulting from diverse pathogenetic mechanisms grouped under a larger umbrella. There is an urgent need for innovative basic science and translational research to 1 better understand FSGS recurrence from a mechanistic perspective; 2 improve risk stratification to predict this outcome; and 3 develop effective therapies. In this conference report, we describe the work of investigators whose state-of-the-art research paves the way for innovative approaches to diagnosis and treatment of the problem and provides hope that we can achieve these objectives for affected patients.
Understanding the complex genetic makeup underlying congenital anomalies of the kidney and urinary tract (CAKUT) is of primary importance to improve diagnosis, stratify risk for later-onset ...complications, and develop therapeutic strategies. Saisawat et al. used homozygosity mapping coupled with next-generation sequencing to identify recessive mutations in TRAP1 in families with isolated CAKUT and with VACTERL association. This study points to a novel player in kidney development, possibly affecting apoptosis and endoplasmic reticulum stress signaling.
Exome sequencing is emerging as a first-line diagnostic method in some clinical disciplines, but its usefulness has yet to be examined for most constitutional disorders in adults, including chronic ...kidney disease, which affects more than 1 in 10 persons globally.
We conducted exome sequencing and diagnostic analysis in two cohorts totaling 3315 patients with chronic kidney disease. We assessed the diagnostic yield and, among the patients for whom detailed clinical data were available, the clinical implications of diagnostic and other medically relevant findings.
In all, 3037 patients (91.6%) were over 21 years of age, and 1179 (35.6%) were of self-identified non-European ancestry. We detected diagnostic variants in 307 of the 3315 patients (9.3%), encompassing 66 different monogenic disorders. Of the disorders detected, 39 (59%) were found in only a single patient. Diagnostic variants were detected across all clinically defined categories, including congenital or cystic renal disease (127 of 531 patients 23.9%) and nephropathy of unknown origin (48 of 281 patients 17.1%). Of the 2187 patients assessed, 34 (1.6%) had genetic findings for medically actionable disorders that, although unrelated to their nephropathy, would also lead to subspecialty referral and inform renal management.
Exome sequencing in a combined cohort of more than 3000 patients with chronic kidney disease yielded a genetic diagnosis in just under 10% of cases. (Funded by the National Institutes of Health and others.).
Pathogenic copy number variants (CNVs) could explain congenital anomalies of the kidney and urinary tract (CAKUT) in 5.29% of the families in our cohort, increasing the percentage of patients with a ...genetic cause to 18% (roughly one in five patients) from the 13% identified via whole-exome sequencing. CNV analyses can help CAKUT patients and their families to identify their genetic etiology.
Congenital anomalies of the kidneys and urinary tract (CAKUT) are the most common cause of chronic kidney disease among children and adults younger than 30 yr. In our previous study, whole-exome sequencing (WES) identified a known monogenic cause of isolated or syndromic CAKUT in 13% of families with CAKUT. However, WES has limitations and detection of copy number variations (CNV) is technically challenging, and CNVs causative of CAKUT have previously been detected in up to 16% of cases.
To detect CNVs causing CAKUT in this WES cohort and increase the diagnostic yield.
We performed a genome-wide single nucleotide polymorphism (SNP)-based CNV analysis on the same CAKUT cohort for whom WES was previously conducted.
We evaluated and classified the CNVs using previously published predefined criteria.
In a cohort of 170 CAKUT families, we detected a pathogenic CNV known to cause CAKUT in nine families (5.29%, 9/170). There were no competing variants on genome-wide CNV analysis or WES analysis. In addition, we identified novel likely pathogenic CNVs that may cause a CAKUT phenotype in three of the 170 families (1.76%).
CNV analysis in this cohort of 170 CAKUT families previously examined via WES increased the rate of diagnosis of genetic causes of CAKUT from 13% on WES to 18% on WES + CNV analysis combined. We also identified three candidate loci that may potentially cause CAKUT.
We conducted a genetics study on families with congenital anomalies of the kidney and urinary tract (CAKUT). We identified gene mutations that can explain CAKUT symptoms in 5.29% of the families, which increased the percentage of genetic causes of CAKUT to 18% from a previous study, so roughly one in five of our patients with CAKUT had a genetic cause. These analyses can help patients with CAKUT and their families in identifying a possible genetic cause.
Membranous Nephropathy (MN) is a rare autoimmune cause of kidney failure. Here we report a genome-wide association study (GWAS) for primary MN in 3,782 cases and 9,038 controls of East Asian and ...European ancestries. We discover two previously unreported loci, NFKB1 (rs230540, OR = 1.25, P = 3.4 × 10
) and IRF4 (rs9405192, OR = 1.29, P = 1.4 × 10
), fine-map the PLA2R1 locus (rs17831251, OR = 2.25, P = 4.7 × 10
) and report ancestry-specific effects of three classical HLA alleles: DRB1*1501 in East Asians (OR = 3.81, P = 2.0 × 10
), DQA1*0501 in Europeans (OR = 2.88, P = 5.7 × 10
), and DRB1*0301 in both ethnicities (OR = 3.50, P = 9.2 × 10
and OR = 3.39, P = 5.2 × 10
, respectively). GWAS loci explain 32% of disease risk in East Asians and 25% in Europeans, and correctly re-classify 20-37% of the cases in validation cohorts that are antibody-negative by the serum anti-PLA2R ELISA diagnostic test. Our findings highlight an unusual genetic architecture of MN, with four loci and their interactions accounting for nearly one-third of the disease risk.
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