Genetic Drivers of Kidney Defects in the DiGeorge Syndrome

Background The DiGeorge syndrome, the most common of the microdeletion syndromes, affects multiple organs, including the heart, the nervous system, and the kidney. It is caused by deletions on chromosome 22q11.2; the genetic driver of the kidney defects is unknown. Methods We conducted a genomewide search for structural variants in two cohorts: 2080 patients with congenital kidney and urinary tract anomalies and 22,094 controls. We performed exome and targeted resequencing in samples obtained from 586 additional patients with congenital kidney anomalies. We also carried out functional studies using zebrafish and mice. Results We identified heterozygous deletions of 22q11.2 in 1.1% of the patients with congenital kidney anomalies and in 0.01% of population controls (odds ratio, 81.5; P=4.5×10(-14)). We localized the main drivers of renal disease in the DiGeorge syndrome to a 370-kb region containing nine genes. In zebrafish embryos, an induced loss of function in snap29, aifm3, and crkl resulted in renal defects; the loss of crkl alone was sufficient to induce defects. Five of 586 patients with congenital urinary anomalies had newly identified, heterozygous protein-altering variants, including a premature termination codon, in CRKL. The inactivation of Crkl in the mouse model induced developmental defects similar to those observed in patients with congenital urinary anomalies. Conclusions We identified a recurrent 370-kb deletion at the 22q11.2 locus as a driver of kidney defects in the DiGeorge syndrome and in sporadic congenital kidney and urinary tract anomalies. Of the nine genes at this locus, SNAP29, AIFM3, and CRKL appear to be critical to the phenotype, with haploinsufficiency of CRKL emerging as the main genetic driver. (Funded by the National Institutes of Health and others.)

Podocytes: the role of lysosomes in the development of nephrotic syndrome

This commentary highlights the article by Guangbi Li et al that links ceramide accumulation in podocytes to cellular damage and nephrotic syndrome

Hidden genetics behind glomerular scars: an opportunity to understand the heterogeneity of focal segmental glomerulosclerosis?

Focal segmental glomerulosclerosis (FSGS) is a complex disease which describes different kinds of kidney defects, not exclusively linked with podocyte defects. Since nephrin mutation was first described in association with early-onset nephrotic syndrome (NS), many advancements have been made in understanding genetic patterns associated with FSGS. New genetic causes of FSGS have been discovered, displaying unexpected genotypes, and recognizing possible site of damage. Many recent large-scale sequencing analyses on patients affected by idiopathic chronic kidney disease (CKD), kidney failure (KF) of unknown origin, or classified as FSGS, have revealed collagen alpha IV genes, as one of the most frequent sites of pathogenic mutations. Also, recent interest in complex and systemic lysosomal storage diseases, such as Fabry disease, has highlighted GLA mutations as possible causes of FSGS. Tubulointerstitial disease, recently classified by KDIGO based on genetic subtypes, when associated with UMOD variants, may phenotypically gain FSGS features, as well as ciliopathy genes or others, otherwise leading to completely different phenotypes, but found carrying pathogenic variants with associated FSGS phenotype. Thus, glomerulosclerosis may conceal different heterogeneous conditions. When a kidney biopsy is performed, the principal objective is to provide an accurate diagnosis. The broad spectrum of phenotypic expression and genetic complexity is demonstrating that a combined path of management needs to be applied. Genetic investigation should not be reserved only to selected cases, but rather part of medical management, integrating with clinical and renal pathology records. FSGS heterogeneity should be interpreted as an interesting opportunity to discover new pathways of CKD, requiring prompt genotype-phenotype correlation. In this review, we aim to highlight how FSGS represents a peculiar kidney condition, demanding multidisciplinary management, and in which genetic analysis may solve some otherwise unrevealed idiopathic cases. Unfortunately there is not a uniform correlation between specific mutations and FSGS morphological classes, as the same variants may be identified in familial cases or sporadic FSGS/NS or manifest a variable spectrum of the same disease. These non-specific features make diagnosis challenging. The complexity of FSGS genotypes requires new directions. Old morphological classification does not provide much information about the responsible cause of disease and misdiagnoses may expose patients to immunosuppressive therapy side effects, mistaken genetic counseling, and misguided kidney transplant programs

MUSIC THERAPY REDUCES ANXIETY AND PAIN AND IMPROVES SATISFACTION IN PATIENTS UNDERGOING PERCUTANEOUS RENAL BIOPSY

BACKGROUND AND AIMS Percutaneous kidney biopsy (PRB) is an invasive procedure performed under local anaesthesia that often creates anxiety, stress and pain in the patient before, during and after the procedure. Music therapy (MT), defined as the clinical- and evidence-based use of music, is administered by a trained professional to achieve individualized goals within a therapeutic relationship between patient, music and music therapist. MT can be used as a complementary non-drug intervention to prevent and treat emotional distress and pain. The main objectives of the study were 1. evaluate the effectiveness of MT in managing anxiety, pain and satisfaction in patients undergoing PRB. 2. investigate the effect of MTI on heart rate variability (HRV). METHOD This study was a two-arm, single-centre, parallel-group and pre–post PRB randomized controlled trial. Patients programmed for PRB were enrolled (n = 80) and assigned to the MT intervention group (MG, n = 40) or standard treatment [control group (CG), n = 40]. MG received, from a FAMI-certified music therapist, a personalized playlist administered during the PRB, adapted to the individual patient. Patient anxiety was assessed before and after PRB using the State Y-1 Trait Anxiety Inventory (STAI-Y1). A visual analog scale (VAS) was used for self-assessment of pain (VAS-P) and satisfaction (VAS-S). Physiological stress parameters (PRE–POST) were assessed using HRV (SDNN, RMSSD, LH/HF, SD1, SD2) from E4 wristbands—Empatica Inc.1. The bracelet was placed 5 min before the patient entered the operating room for the procedure and removed after the completion of the PRB. The data of each session were divided into two segments: (1) pre, before the administration of the local anesthetic and (2) post, after the conclusion of the biopsy. RESULTS A statistically significant difference in anxiety levels was observed between the MG and CG groups (35.35 ± 6.208 versus 42.83 ± 9.027; P < 0.001, Fig. 1). The MG group showed significantly lower VAS-P values ​​(4.95 ± 1.377 versus 6.28 ± 1.281; P < 0.001, Fig. 2) and higher VAS-S values ​​(7.75 ± 0.981 versus 6.03 ± 0.800; P < 0.001) after PRB compared with the CG group (Fig. 3). The SDNN (P < 0.034), RMSDD (P < 0.04) and SD2 (P < 0.027) measurements of HRV were significantly higher in MG than in CG, while LF/HF decreased (P < 0.033). CONCLUSION This study supports the efficacy of MT in reducing anxiety and pain and improving satisfaction in patients undergoing PRB. MT modulates the autonomic nervous system, reducing sympathetic activity, increasing parasympathetic activity and inducing physiological relaxation

Convalescent plasma therapy in aHUS patient with SARS-CoV-2 infection

Endotheliosis, thrombotic microangiopathy and complement system over activation have been described as pathologic features of tissue damage in the setting of coronavirus disease. Interestingly, complement-mediated cell injury is also a typical feature of atypical Hemolytic Uremic Syndrome. Indeed, a growing body of literature has described a higher risk of microangiopathy recurrence, in aHUS patients who test positive for SARS-CoV-2. The correct clinical and therapeutic management patients with a history of HUS and SARS-CoV-2 infection is not well established.We report a case of SARS-CoV-2 infection in an aHUS patient who did not develop a recurrence of the disease and that was successfully treated with convalescent immune plasma therapy

What Is Hidden in Patients with Unknown Nephropathy? Genetic Screening Could Be the Missing Link in Kidney Transplantation Diagnosis and Management.

Between 15-20% of patients with end stage renal disease (ESRD) do not know the cause of the primary kidney disease and can develop complications after kidney transplantation. We performed a genetic screening in 300 patients with kidney transplantation, or undiagnosed primary renal disease, in order to identify the primary disease cause and discriminate between overlapping phenotypes. We used a custom-made panel for next-generation sequencing (Agilent technology, Santa Clara, CA, USA), including genes associated with Fabry disease, podocytopaties, complement-mediated nephropathies and Alport syndrome-related diseases. We detected candidate diagnostic variants in genes associated with nephrotic syndrome and Focal Segmental Glomerulosclerosis (FSGS) in 29 out of 300 patients, solving about 10% of the probands. We also identified the same genetic cause of the disease (PAX2: c.1266dupC) in three family members with different clinical diagnoses. Interestingly we also found one female patient carrying a novel missense variant, c.1259C>A (p.Thr420Lys), in the GLA gene not previously associated with Fabry disease, which is in silico defined as a likely pathogenic and destabilizing, and associated with a mild alteration in GLA enzymatic activity. The identification of the specific genetic background may provide an opportunity to evaluate the risk of recurrence of the primary disease, especially among patient candidates living with a donor kidney transplant

Erratum: Exome-wide Association Study Identifies GREB1L Mutations in Congenital Kidney Malformations (The American Journal of Human Genetics (2017) 101(5) (789–802) (S0002929717303877) (10.1016/j.ajhg.2017.09.018))

(The American Journal of Human Genetics 101, 789–802; November 2, 2017) In the version of this paper originally published, the author's name Anna Materna-Kiryluk was incorrectly hyphenated. It appears correctly here and online. The authors apologize for this error

De novo TRIM8 variants impair its protein localization to nuclear bodies and cause developmental delay, epilepsy, and focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is the main pathology underlying steroid-resistant nephrotic syndrome (SRNS) and a leading cause of chronic kidney disease. Monogenic forms of pediatric SRNS are predominantly caused by recessive mutations, while the contribution of de novo variants (DNVs) to this trait is poorly understood. Using exome sequencing (ES) in a proband with FSGS/SRNS, developmental delay, and epilepsy, we discovered a nonsense DNV in TRIM8, which encodes the E3 ubiquitin ligase tripartite motif containing 8. To establish whether TRIM8 variants represent a cause of FSGS, we aggregated exome/genome-sequencing data for 2,501 pediatric FSGS/SRNS-affected individuals and 48,556 control subjects, detecting eight heterozygous TRIM8 truncating variants in affected subjects but none in control subjects (p = 3.28 × 10-11). In all six cases with available parental DNA, we demonstrated de novo inheritance (p = 2.21 × 10-15). Reverse phenotyping revealed neurodevelopmental disease in all eight families. We next analyzed ES from 9,067 individuals with epilepsy, yielding three additional families with truncating TRIM8 variants. Clinical review revealed FSGS in all. All TRIM8 variants cause protein truncation clustering within the last exon between residues 390 and 487 of the 551 amino acid protein, indicating a correlation between this syndrome and loss of the TRIM8 C-terminal region. Wild-type TRIM8 overexpressed in immortalized human podocytes and neuronal cells localized to nuclear bodies, while constructs harboring patient-specific variants mislocalized diffusely to the nucleoplasm. Co-localization studies demonstrated that Gemini and Cajal bodies frequently abut a TRIM8 nuclear body. Truncating TRIM8 DNVs cause a neuro-renal syndrome via aberrant TRIM8 localization, implicating nuclear bodies in FSGS and developmental brain disease.</p

Betekening door een gerechtsdeurwaarder-lastgever aan de gekozen woonplaats i.c. zijn eigen kantoor: een bizarre driehoeksverhouding

(The American Journal of Human Genetics 101, 789â\u80\u93802; November 2, 2017) In the version of this paper originally published, the author's name Anna Materna-Kiryluk was incorrectly hyphenated. It appears correctly here and online. The authors apologize for this error