Renal agenesis and hypodysplasia (RHD) are major causes of pediatric chronic kidney disease and are highly genetically heterogeneous. We conducted whole-exome sequencing in 202 case subjects with RHD ...and identified diagnostic mutations in genes known to be associated with RHD in 7/202 case subjects. In an additional affected individual with RHD and a congenital heart defect, we found a homozygous loss-of-function (LOF) variant in SLIT3, recapitulating phenotypes reported with Slit3 inactivation in the mouse. To identify genes associated with RHD, we performed an exome-wide association study with 195 unresolved case subjects and 6,905 control subjects. The top signal resided in GREB1L, a gene implicated previously in Hoxb1 and Shha signaling in zebrafish. The significance of the association, which was p = 2.0 × 10−5 for novel LOF, increased to p = 4.1 × 10−6 for LOF and deleterious missense variants combined, and augmented further after accounting for segregation and de novo inheritance of rare variants (joint p = 2.3 × 10−7). Finally, CRISPR/Cas9 disruption or knockdown of greb1l in zebrafish caused specific pronephric defects, which were rescued by wild-type human GREB1L mRNA, but not mRNA containing alleles identified in case subjects. Together, our study provides insight into the genetic landscape of kidney malformations in humans, presents multiple candidates, and identifies SLIT3 and GREB1L as genes implicated in the pathogenesis of RHD.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nephrocalcinosis can manifest as frequent urination, haematuria and recurrent urinary tract infections, as well as a decrease in bone mineral density, increasing the risk of osteoporosis. Excessive ...urinary calcium excretion may have a genetic basis, including mutations within the genes encoding vitamin D3 metabolising enzymes. This paper presents a report of a 7-year follow-up of a boy in whom abdominal ultrasound incidentally detected nephrocalcinosis. The patient was confirmed to have a homozygous R396W mutation in the CYP24A1 gene, which encodes an enzyme responsible for inactivating calcitriol and protecting the cell from vitamin D3 intoxication. Radiological examinations showed a decrease in bone mineral density in the spine. Genetic factors, especially those related to abnormal vitamin D3 metabolism, should be considered in the differential diagnosis of incidentally detected nephrocalcinosis. Children with excessive urinary calcium excretion are at particular risk of developing skeletal complications, including osteopenia and osteoporosis.
Post-translational modifications are necessary for collagen precursor molecules (procollagens) to acquire final shape and function. However, the mechanism and contribution of collagen modifications ...that occur outside the endoplasmic reticulum and Golgi are not understood. We discovered that VIPAR, with its partner proteins, regulate sorting of lysyl hydroxylase 3 (LH3, also known as PLOD3) into newly identified post-Golgi collagen IV carriers and that VIPAR-dependent sorting is essential for modification of lysines in multiple collagen types. Identification of structural and functional collagen abnormalities in cells and tissues from patients and murine models of the autosomal recessive multisystem disorder Arthrogryposis, Renal dysfunction and Cholestasis syndrome caused by VIPAR and VPS33B deficiencies confirmed our findings. Thus, regulation of post-Golgi LH3 trafficking is essential for collagen homeostasis and for the development and function of multiple organs and tissues.
•Multisystem inflammatory syndrome in children is a new disease that causes therapeutic difficulties for pediatricians.•Despite recommendations for the treatment of multisystem inflammatory syndrome ...in children, antibiotic therapy is popular.•Early infectious consultation of a patient with multisystem inflammatory syndrome in children can limit unnecessary antibiotics.
Multisystem inflammatory syndrome in children (MIS-C) is the result of an immune response triggered by a previous exposure to SARS-CoV-2. The clinical presentation of MIS-C overlaps with other life-threatening bacterial infections, in which antimicrobials are the mainstay therapy. The aim of study was to describe the use of antibiotics in children with MIS-C in Poland.
The analysis of 345 children reported from 42 Polish cities to the national MultiOrgan Inflammatory Syndromes COVID-19 Related Study (MOIS-CoR Study) from June 2020 to April 2021.
At least one antibiotic was used in 310 (90%) children, mainly third-generation cephalosporin (251/310). Broad-spectrum antibiotics were used in 258 (75%) children and 224 (87%) received this treatment for more than 3 days. Concentrations of serum procalcitonin >2 µg/l and the presence of lower respiratory symptoms were associated with increased odds of receiving any antibiotic.
Although bacterial infections in patients with MIS-C are uncommon, we show that MIS-C poses a challenge to clinicians who are faced with the decision to start, continue, or stop antimicrobial therapy. Antibiotic stewardship in patients with MIS-C should be improved to ensure that likely pathogens are treated and that antimicrobials are stopped when bacterial infections are excluded and the diagnosis of MIS-C is made.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Introduction
DSTYK
encodes dual serine/threonine and tyrosine protein kinase.
DSTYK
has been associated with autosomal-dominant congenital anomalies of the kidney and urinary tract and with ...autosomal-recessive hereditary spastic paraplegia type 23. Here, we report a father and his two dizygotic twin sons carrying a novel heterozygous missense variant in
DSTYK
, presenting with early onset lower urinary tract dysfunction due to dysfunctional voiding. Moreover, in the later course of the disease, both sons presented with bilateral spasticity in their lower limbs, brisk reflexes, and absence seizures.
Materials and methods
Exome sequencing in the affected father and his affected sons was performed. The sons presented clinically with urinary hesitancy, dysfunctional voiding, and night incontinence till adolescence, while the father reported difficulty in voiding. In the sons, cystoscopy excluded urethral valves and revealed hypertrophy of the bladder neck and trabeculated bladder. Additionally, both sons were diagnosed with absence epilepsy in early childhood. Filtering of exome data focused on rare (MAF < 0.01%), autosomal-dominant variants, predicted to be deleterious, residing in highly conserved regions of the exome.
Results
Exome analysis identified a novel, heterozygous missense variant (c.271C>A (p.Leu91Met)) in
DSTYK
segregating with the disease. In silico prediction analyses uniformly rated the variant to be deleterious suggesting the variant to be disease-causing in the family.
Conclusion
To the best of our knowledge, this is the first report of early onset dysfunctional voiding, seizures, and bilateral spasticity of the lower limbs associated with a novel heterozygous dominant missense variant in
DSTYK
.
Posterior urethral valves (PUV) are the commonest cause of end-stage renal disease in children, but the genetic architecture of this rare disorder remains unknown. We performed a sequencing-based ...genome-wide association study (seqGWAS) in 132 unrelated male PUV cases and 23,727 controls of diverse ancestry, identifying statistically significant associations with common variants at 12q24.21 (p=7.8 × 10
; OR 0.4) and rare variants at 6p21.1 (p=2.0 × 10
; OR 7.2), that were replicated in an independent European cohort of 395 cases and 4151 controls. Fine mapping and functional genomic data mapped these loci to the transcription factor
and planar cell polarity gene
, respectively, the encoded proteins of which were detected in the developing urinary tract of human embryos. We also observed enrichment of rare structural variation intersecting with candidate
-regulatory elements, particularly inversions predicted to affect chromatin looping (p=3.1 × 10
). These findings represent the first robust genetic associations of PUV, providing novel insights into the underlying biology of this poorly understood disorder and demonstrate how a diverse ancestry seqGWAS can be used for disease locus discovery in a rare disease.
Lower urinary tract obstruction (LUTO) is, in most cases, caused by anatomical blockage of the bladder outlet. The most common form are posterior urethral valves (PUVs), a male-limited phenotype. ...Here, we surveyed the genome of 155 LUTO patients to identify disease-causing CNVs. Raw intensity data were collected for CNVs detected in LUTO patients and 4.392 healthy controls using CNVPartition, QuantiSNP and PennCNV. Overlapping CNVs between patients and controls were discarded. Additional filtering implicated CNV frequency in the database of genomic variants, gene content and final visual inspection detecting 37 ultra-rare CNVs. After, prioritization qPCR analysis confirmed 3 microduplications, all detected in PUV patients. One microduplication (5q23.2) occurred de novo in the two remaining microduplications found on chromosome 1p36.21 and 10q23.31. Parental DNA was not available for segregation analysis. All three duplications comprised 11 coding genes: four human specific lncRNA and one microRNA. Three coding genes (
,
,
) and the microRNA MIR107 have previously been shown to be expressed in the developing urinary tract of mouse embryos. We propose that duplications, rare or de novo, contribute to PUV formation, a male-limited phenotype.
Cystinuria is an inherited disorder that results in increased excretion of cystine in the urine. It accounts for about 1-2% of pediatric kidney stones. In this study, we sought to identify the ...clinical characteristics of patients with cystinuria in a national cohort.
This was a retrospective study involving 30 patients from the Polish Registry of Inherited Tubulopathies. Initial data and that from a 6-month follow-up were analyzed. Mutational analysis was performed by targeted Sanger sequencing and, if applicable, MLPA analysis was used to detect large rearrangements.
SLC7A9 mutations were detected in 15 children (50%; 10 males, 5 females), SLC3A1 mutations in 14 children (47%; 5 males, 9 females), and bigenic mutations in one male patient. The first clinical symptoms of the disease were detected at a median of 48 months of age (range 3-233 months). When individuals with different mutations were compared, there were no differences identified in gender, age of diagnosis, presence of UTI or urolithiasis, eGFR, calcium, or cystine excretion. The most common initial symptoms were urolithiasis in 26 patients (88%) and urinary tract infections in 4 patients (13%). Urological procedures were performed in 18 out of 30 (60%).
The clinical course of cystinuria is similar among patients, regardless of the type of genetic mutation. Most patients require surgery before diagnosis or soon after it. Patients require combined urological and pharmacological treatment for prevention of stone recurrence and renal function preservation.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Background: Hyperuricemia is recognized as an important feature of nephropathy, associated with a mutation in the hepatocyte nuclear factor-1B (HNF1B) gene, and could serve as a useful marker of the ...disease. However, neither a causal relationship nor its predictive value have been proven. The purpose of this study was to assess this in children with renal malformations, both with (mut+) and without HNF1B mutations (mut-). Methods: We performed a retrospective analysis of clinical characteristics of pediatric patients tested for HNF1B mutations, collected in a national registry. Results: 108 children were included in the study, comprising 43 mut+ patients and 65 mut- subjects. Mean sUA was higher and hyperuricemia more prevalent (42.5% vs. 15.4%) in HNF1B carriers. The two groups were similar with respect to respect to age, sex, anthropometric parameters, hypertension, and renal function. Renal function, fractional excretion of uric acid and parathyroid hormone level were independent predictors of sUA. The potential of hyperuricemia to predict mutation was low, and addition of hyperuricemia to a multivariate logistic regression model did not increase its accuracy. Conclusions: Hyperuricemia is an early and common feature of HNF1B nephropathy. A strong association of sUA with renal function and parathyroid hormone limits its utility as a reliable marker to predict HNF1B mutation among patients with kidney anomalies.
Background
The oculocerebrorenal syndrome of Lowe (OCRL) is a rare X-linked multi-systemic disorder, almost always characterized by the triad of congenital cataract, cognitive and behavioral ...impairment and a proximal tubulopathy.
Methods
Twenty-eight novel patients with suspected Lowe syndrome were studied.
Results
All patients carried
OCRL
gene defects with mutational hot spots at CpG dinucleotides. Mutations previously unknown in Lowe syndrome were observed in ten of the 28 patients, and carriership was identified in 30.4 % of the mothers investigated. Mapping the exact breakpoints of a complete
OCRL
gene deletion revealed involvement of several flanking repeat elements. We noted a similar pattern of documented clinically relevant symptoms, and even though the patient cohort comprised relatively young patients, 32 % of these patients already showed advanced chronic kidney disease. Thrombocytopenia was seen in several patients, and hyperosmia and/or hyperacusis were reported recurrently. A p.Asp523Asn mutation in a Polish patient, associated with the typical cerebrorenal spectrum but with late cataract (10 year), was also evident in two milder affected Italian brothers with ocular involvement of similar progression.
Conclusions
We have identified clinical features in 28 patients with suspected Lowe syndrome that had not been recognized in Lowe syndrome prior to our study. We also provide further evidence that
OCRL
mutations cause a phenotypic continuum with selective and/or time-dependent organ involvement. At least some of these mutants might exhibit a genotype–phenotype correlation.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
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